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1.
Braz. j. biol ; 84: e252735, 2024. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1355873

RESUMO

Abstract Growth of plants is severely reduced due to water stress by affecting photosynthesis including photosystem II (PSII) activity and electron transport. This study emphasised on comparative and priority targeted changes in PSII activity due to progressive drought in seven populations of Panicum antidotale (P. antidotale) collected from Cholistan Desert and non-Cholistan regions. Tillers of equal growth of seven populations of P. antidotale grown in plastic pots filled with soil were subjected progressive drought by withholding water irrigation for three weeks. Progressive drought reduced the soil moisture content, leaf relative water content, photosynthetic pigments and fresh and dry biomass of shoots in all seven populations. Populations from Dingarh Fort, Dingarh Grassland and Haiderwali had higher growth than those of other populations. Cholistani populations especially in Dingarh Grassland and Haiderwali had greater ability of osmotic adjustment as reflected by osmotic potential and greater accumulation of total soluble proteins. Maximum H2O2 under water stress was observed in populations from Muzaffargarh and Khanewal but these were intermediate in MDA content. Under water stress, populations from Muzaffargarh and Dingarh Fort had greater K+ accumulation in their leaves. During progressive drought, non-Cholistani populations showed complete leaf rolling after 23 days of drought, and these populations could not withstand with more water stress condition while Cholistani populations tolerated more water stress condition for 31 days. Moreover, progressive drought caused PSII damages after 19 days and it became severe after 23 days in non-Cholistani populations of P. antidotale than in Cholistani populations.


Resumo O crescimento das plantas é severamente reduzido devido ao estresse hídrico, afetando a fotossíntese, incluindo a atividade do fotossistema II (PSII) e o transporte de elétrons. Este estudo enfatizou as mudanças comparativas e prioritárias na atividade do PSII devido à seca progressiva em sete populações de Panicum antidotale (P. antidotale) coletadas no Deserto do Cholistão e regiões fora do Cholistão. Perfilhos de igual crescimento de sete populações de P. antidotale cultivadas em vasos de plástico cheios de solo foram submetidos à seca progressiva, retendo a irrigação com água por três semanas. A seca progressiva reduziu o teor de umidade do solo, teor de água relativo nas folhas, pigmentos fotossintéticos e biomassa fresca e seca dos brotos em todas as sete populações. Populações de Dingarh Fort, Dingarh Grassland e Haiderwali tiveram maior crescimento do que as de outras populações. As populações de Cholistani, especialmente em Dingarh Grassland e Haiderwali, apresentaram maior capacidade de ajuste osmótico, refletido pelo potencial osmótico e maior acúmulo de proteínas solúveis totais. H2O2 máximo sob estresse hídrico foi observado em populações de Muzaffargarh e Khanewal, mas estas foram intermediárias no conteúdo de MDA. Sob estresse hídrico, as populações de Muzaffargarh e Dingarh Fort tiveram maior acúmulo de K+ em suas folhas. Durante a seca progressiva, as populações não cholistanesas mostraram rolagem completa das folhas após 23 dias de seca, e essas populações não conseguiram suportar mais condições de estresse hídrico, enquanto as populações cholistani toleraram mais condições de estresse hídrico por 31 dias. Além disso, a seca progressiva causou danos ao PSII após 19 dias e tornou-se severa após 23 dias em populações não cholistanesas de P. antidotale do que em populações cholistanesas.


Assuntos
Panicum , Fotossíntese , Folhas de Planta , Dessecação , Secas , Peróxido de Hidrogênio
2.
Braz. j. biol ; 83: e245379, 2023. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1339405

RESUMO

Abstract Population growth is increasing rapidly around the world, in these consequences we need to produce more foods to full fill the demand of increased population. The world is facing global warming due to urbanizations and industrialization and in this concerns plants exposed continuously to abiotic stresses which is a major cause of crop hammering every year. Abiotic stresses consist of Drought, Salt, Heat, Cold, Oxidative and Metal toxicity which damage the crop yield continuously. Drought and salinity stress severally affected in similar manner to plant and the leading cause of reduction in crop yield. Plants respond to various stimuli under abiotic or biotic stress condition and express certain genes either structural or regulatory genes which maintain the plant integrity. The regulatory genes primarily the transcription factors that exert their activity by binding to certain cis DNA elements and consequently either up regulated or down regulate to target expression. These transcription factors are known as masters regulators because its single transcript regulate more than one gene, in this context the regulon word is fascinating more in compass of transcription factors. Progress has been made to better understand about effect of regulons (AREB/ABF, DREB, MYB, and NAC) under abiotic stresses and a number of regulons reported for stress responsive and used as a better transgenic tool of Arabidopsis and Rice.


Resumo O crescimento populacional está aumentando rapidamente em todo o mundo, e para combater suas consequências precisamos produzir mais alimentos para suprir a demanda do aumento populacional. O mundo está enfrentando o aquecimento global devido à urbanização e industrialização e, nesse caso, plantas expostas continuamente a estresses abióticos, que é uma das principais causas do martelamento das safras todos os anos. Estresses abióticos consistem em seca, sal, calor, frio, oxidação e toxicidade de metais que prejudicam o rendimento da colheita continuamente. A seca e o estresse salino são afetados de maneira diversa pela planta e são a principal causa de redução da produtividade das culturas. As plantas respondem a vários estímulos sob condições de estresse abiótico ou biótico e expressam certos genes estruturais ou regulatórios que mantêm a integridade da planta. Os genes reguladores são principalmente os fatores de transcrição que exercem sua atividade ligando-se a certos elementos cis do DNA e, consequentemente, são regulados para cima ou para baixo para a expressão alvo. Esses fatores de transcrição são conhecidos como reguladores mestres porque sua única transcrição regula mais de um gene; nesse contexto, a palavra regulon é mais fascinante no âmbito dos fatores de transcrição. Progresso foi feito para entender melhor sobre o efeito dos regulons (AREB / ABF, DREB, MYB e NAC) sob estresses abióticos e uma série de regulons relatados como responsivos ao estresse e usados ​​como uma melhor ferramenta transgênica de Arabidopsis e Rice.


Assuntos
Regulon/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo , Estresse Fisiológico/genética , Plantas Geneticamente Modificadas/genética , Secas
3.
Braz. j. biol ; 83: e242708, 2023. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1339382

RESUMO

Abstract MicroRNAs (miRNAs) are essential nonprotein-coding genes. In a range of organisms, miRNAs has been reported to play an essential role in regulating gene expressions at post-transcriptional level. They participate in most of the stress responsive processes in plants. Drought is an ultimate abiotic stress that affects the crop production. Therefore understanding drought stress responses are essential to improve the production of agricultural crops. Throughout evolution, plants have developed their own defense systems to cope with the adversities of environmental stresses. Among defensive mechanisms include the regulations of gene expression by miRNAs. Drought stress regulates the expression of some of the functionally conserved miRNAs in different plants. The given properties of miRNAs provide an insight to genetic alterations and enhancing drought resistance in cereal crops. The current review gives a summary to regulatory mechanisms in plants as well as miRNAs response to drought stresses in cereal crops. Some possible approaches and guidelines for the exploitation of drought stress miRNA responses to improve cereal crops are also described.


Resumo MicroRNAs (miRNAs) são genes essenciais não codificadores de proteínas. Em uma variedade de organismos, foi relatado que miRNAs desempenham papel essencial na regulação da expressão gênica em nível pós-transcricional. Eles participam da maioria dos processos responsivos ao estresse nas plantas. A seca é um estresse abiótico final que afeta a produção agrícola. Portanto, compreender as respostas ao estresse da seca é essencial para melhorar a produção de safras agrícolas. Ao longo da evolução, as plantas desenvolveram seus próprios sistemas de defesa para lidar com as adversidades do estresse ambiental. Entre os mecanismos de defesa está a regulação da expressão gênica por miRNAs. O estresse hídrico regula a expressão de alguns dos miRNAs funcionalmente conservados em diferentes plantas. As propriedades dadas dos miRNAs fornecem uma visão das alterações genéticas e aumentam a resistência à seca nas safras de cereais. A revisão atual apresenta um resumo dos mecanismos regulatórios nas plantas, bem como a resposta dos miRNAs ao estresse hídrico nas plantações de cereais. Algumas abordagens e diretrizes possíveis para a exploração das respostas do miRNA ao estresse da seca para melhorar as safras de cereais também são descritas.


Assuntos
MicroRNAs/genética , Secas , Estresse Fisiológico/genética , Produtos Agrícolas/genética , Produção Agrícola
4.
PLoS One ; 17(9): e0274915, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36126078

RESUMO

BACKGROUND: Wheat (Triticum aestivum L.) is a major food crop worldwide. Low soil phosphorus content and drought are the main constraints on wheat production in Xinjiang, China. METHODS: In this study, the ionic and metabolic responses of one wheat variety ("Xindong20") to drought stress simulated by using polyethylene glycol 6000 (PEG-6000) were investigated under low phosphorus (LP) and conventional phosphorus (CP) conditions by analysing wheat mineral elements and metabolites. Besides, due to xanthohumol was the metabolite with the most significant difference in expression detected in "Xindong 20", two wheat variety "Xindong20 and Xindong 23" were selected to conduct the germination test simultaneously, to further verify the function of xanthohumol in wheat growth. Xanthohumol was mixed with PEG solution (20%) to prepare PEG solutions with different concentrations (0%, 0.1%, 0.5%, and 1%) of xanthohumol. Then wheat grains were soaked in the solutions for 20 hours, followed by a germination test. After 7 days, the indicators including shoot length, max root length, and root number were determined to identify whether the metabolite was beneficial to improve the drought tolerance of wheat. RESULTS: The results showed that the root density and volume of wheat in LP treatment were higher than those in CP treatment. The roots underwent programmed cell death both in LP and CP treatments under PEG-6000-simulated drought stress, however, the DNA degradation in root cells in LP treatment was lower than that in CP treatment after rehydration for 3 d. Before drought stress, the malondialdehyde (MDA) content in shoot and the peroxidase (POD) activity in root in LP treatment were significantly higher than those in CP treatment, while the soluble sugar content and chlorophyll content in LP treatment were significantly lower than those in CP treatment. During drought stress, the POD activity maintained at a high level and the soluble sugar content gradually increased in LP treatment. After rehydration, the MDA content still maintained at a high level in LP treatment, the superoxide dismutase (SOD) activity increased, and the contents of soluble sugar and chlorophyll were significantly higher than those in CP treatment. The analysis of mineral elements and metabolites showed that the wheat in CP treatment was more sensitive to drought stress than that in LP treatment. Besides, the effect of drought stress was greater on shoot than on root in CP treatment, while it was opposite in LP treatment. The effect of drought stress on sugar metabolism gradually increased. Germination assays showed that 0.1% exogenous xanthohumol addition could significantly increase the shoot length of the two wheat varieties under drought stress. CONCLUSION: Appropriate low phosphorus supply could increase antioxidant enzyme activity in wheat, and enhance sugar metabolism to regulate osmotic balance, as well as the accumulation of various organic acids to maintain the intracellular ion homeostasis. Therefore, compared to the conventional phosphorus supply level, appropriate low phosphorus supply can significantly improve the drought tolerance of wheat. Additionally, addition of 0.1% exogenous xanthohumol, an important differential expressed metabolite in drought-stressed wheat, could effectively promote wheat shoot growth under drought stress.


Assuntos
Secas , Plântula , Antioxidantes/metabolismo , Clorofila/metabolismo , DNA/metabolismo , Flavonoides , Malondialdeído/metabolismo , Peroxidases/metabolismo , Fósforo/metabolismo , Polietilenoglicóis , Propiofenonas , Solo , Açúcares/metabolismo , Superóxido Dismutase/metabolismo , Triticum/genética
6.
Sci Rep ; 12(1): 15432, 2022 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-36104454

RESUMO

Drought is a natural disaster affects water resources, agriculture, and social and economic development due to its long-term and frequent occurrence. It is crucial to characterize and monitor drought and its propagation to minimize the impact. However, spatiotemporal assessment of drought characteristics over India at the sub-basin scale based on terrestrial water storage is unexplored. In this study, the Terrestrial water storage anomalies (TWSA) obtained from a Gravity Recovery and Climate Experiment and precipitation data are used to characterize the propagation of drought. Combined Climatological Deviation Index (CCDI) and GRACE-Drought Severity Index (GRACE-DSI) were computed as CCDI utilizes both precipitation and TWSA data while GRACE-DSI uses only TWSA data. Our results showed that GRACE-DSI exhibits significant negative trends over most of the Indian sub-basins compared to CCDI, indicating that most of the drought events are due to depletion of TWS. While other sub-basins show changing trends for GRACE-DSI and CCDI. The number of sub-basins showing significant negative trends for GRACE-DSI is more than that for CCDI. Hence TWS is depleting for most of the subbasins in India. Our results show that Indo-Gangetic plains face many drought events during 2002-2004, 2009-2014 & 2015-2017. Maximum drought duration and drought severity obtained for the area of North Ladakh (not draining into Indus basins) by GRACE-DSI are 26 months (2002-2004) and - 44.2835, respectively. The maximum drought duration and drought severity obtained for the Shyok sub-basin by CCDI is 17 months (2013-2015) and - 13.4392, respectively. Monthly trend analysis revealed that 39 & 23 no. of sub-basins show significant negative GRACE-DSI trends for October and CCDI for November, respectively. At the same time, the seasonal trend shows that total 34 and 14 sub-basins exhibited a significant negative trend at post-monsoon Kharif season for both the GRACE-DSI & CCDI, respectively.


Assuntos
Secas , Meteorologia , Clima , Estações do Ano , Água
7.
BMC Plant Biol ; 22(1): 440, 2022 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-36104814

RESUMO

BACKGROUND: Despite the importance of root hydraulics, there is little research on the in situ dynamic responses of embolism formation and embolism repair of roots distributed in different soil depths in response to different water regimes. RESULTS: The vessel diameter, hydraulic conductivity, and vulnerability to cavitation were in the order of deep root > shallow root > branch. The midday PLC of shallow root was the highest in the dry season, while the midday PLC of deep root slightly higher than that of branch with no significant difference in the two seasons. The capacity of embolism repair of roots was significantly greater than that of branch both in dry season and wet season. The xylem pressure was in the order of deep roots > shallow root > branch, and it was negative in most of the time for the latter two in the dry season, but positive for both of the roots during the observation period in the wet season. The NSC and starch content in roots were significantly higher than those in branches, especially in the dry season. In contrast, roots had lower content of soluble sugar. CONCLUSIONS: The relatively stable water condition in soil, especially in the deep layers, is favorable for the development of larger-diameter vessels in root xylem, however it cannot prevent the root from forming embolism. The mechanism of embolism repair may be different in different parts of plants. Deep roots mainly depend on root pressure to refill the embolized vessels, while branches mainly depend on starch hydrolysis to soluble sugars to do the work, with shallow roots shifted between the two mechanisms in different moisture regimes. There is theoretically an obvious trade-off between conducting efficiency and safety over deep roots, shallow roots and branches. But in natural conditions, roots do not necessarily suffer more severe embolism than branches, maybe due to their root pressure-driven embolism repair and relatively good water conditions.


Assuntos
Secas , Juglans , Raízes de Plantas/fisiologia , Transpiração Vegetal/fisiologia , Estações do Ano , Solo/química , Amido , Água/fisiologia , Xilema/fisiologia
8.
Science ; 377(6612): 1248-1249, 2022 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-36108012

RESUMO

Drought spurs efforts to restore shrinking lake's water supplies.


Assuntos
Lagos , Salinidade , Secas
9.
BMC Plant Biol ; 22(1): 445, 2022 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-36114467

RESUMO

BACKGROUND: Drought is a significant condition that restricts vegetation growth on the Tibetan Plateau. Artemisia wellbyi is a unique semi-shrub-like herb in the family Compositae, which distributed in northern and northwest of Tibetan Plateau. It is a dominant species in the community that can well adapt to virous environment stress, such as drought and low temperature. Therefore, A. wellbyi. has a potential ecological value for soil and water conservation of drought areas. Understanding the molecular mechanisms of A. wellbyi. that defense drought stress can acquire the key genes for drought resistance breeding of A. wellbyi. and provide a theoretical basis for vegetation restoration of desertification area. However, they remain unclear. Thus, our study compared the transcriptomic characteristics of drought-tolerant "11" and drought-sensitive "6" material of A. wellbyi under drought stress. RESULTS: A total of 4875 upregulated and 4381 downregulated differentially expressed genes (DEGs) were induced by drought in the tolerant material; however, only 1931 upregulated and 4174 downregulated DEGs were induced by drought in the sensitive material. The photosynthesis and transcriptional regulation differed significantly with respect to the DEGs number and expression level. We found that CDPKs (calmodulin-like domain protein kinases), SOS3 (salt overly sensitive3), MAPKs (mitogen-activated protein kinase cascades), RLKs (receptor like kinase), and LRR-RLKs (repeat leucine-rich receptor kinase) were firstly involved in response to drought stress in drought tolerant A. wellbyi. Positive regulation of genes associated with the metabolism of ABA (abscisic acid), ET (ethylene), and IAA (indole acetic acid) could play a crucial role in the interaction with other transcriptional regulatory factors, such as MYBs (v-myb avian myeloblastosis viral oncogene homolog), AP2/EREBPs (APETALA2/ethylene-responsive element binding protein family), WRKYs, and bHLHs (basic helix-loop-helix family members) and receptor kinases, and regulate downstream genes for defense against drought stress. In addition, HSP70 (heat shock protein70) and MYB73 were considered as the hub genes because of their strong association with other DEGs. CONCLUSIONS: Positive transcriptional regulation and negative regulation of photosynthesis could be associated with better growth performance under drought stress in the drought-tolerant material. In addition, the degradation of sucrose and starch in the tolerant A. wellbyi to alleviate osmotic stress and balance excess ROS. These results highlight the candidate genes that are involved in enhancing the performance of drought-tolerant A. wellbyi and provide a theoretical basis for improving the performance of drought-resistant A. wellbyi.


Assuntos
Artemisia , Transcriptoma , Ácido Abscísico , Artemisia/genética , Calmodulina/genética , Meios de Contraste , Secas , Etilenos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Leucina/genética , Proteínas Quinases Ativadas por Mitógeno/genética , Melhoramento Vegetal , Proteínas Quinases/genética , Espécies Reativas de Oxigênio , Solo , Amido , Sacarose
10.
Proc Biol Sci ; 289(1982): 20221034, 2022 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-36069017

RESUMO

While droughts, intensified by climate change, have been affecting forests worldwide, pest epidemics are a major source of uncertainty for assessing drought impacts on forest trees. Thus far, little information has documented the adaptability and evolvability of traits related to drought and pests simultaneously. We conducted common-garden experiments to investigate how several phenotypic traits (i.e. height growth, drought avoidance based on water-use efficiency inferred from δ13C and pest resistance based on defence traits) interact in five mature lodgepole pine populations established in four progeny trials in western Canada. The relevance of interpopulation variation in climate sensitivity highlighted that seed-source warm populations had greater adaptive capability than cold populations. In test sites, warming generated taller trees with higher δ13C and increased the evolutionary potential of height growth and δ13C across populations. We found, however, no pronounced gradient in defences and their evolutionary potential along populations or test sites. Response to selection was weak in defences across test sites, but high for height growth particularly at warm test sites. Response to the selection of δ13C varied depending on its selective strength relative to height growth. We conclude that warming could promote the adaptability and evolvability of growth response and drought avoidance with a limited evolutionary influence from pest (biotic) pressures.


Assuntos
Secas , Pinus , Mudança Climática , Florestas , Pinus/genética , Árvores/fisiologia
11.
J Plant Physiol ; 277: 153807, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36095952

RESUMO

Annual ryegrass is a widely cultivated forage grass with rapid growth and high productivity. However, drought is one of the abiotic stresses affecting ryegrass growth and quality. In this study, we compared the physiological and transcriptome responses of Chuansi No.1 (drought-tolerant, DT) and Double Barrel (drought-sensitive, DS) under drought stress simulated by PEG-6000 for 7 days. The results showed that Chuansi No. 1 had stronger physiological and biochemical parameters such as root properties, water content, osmotic adjustment ability and antioxidant ability. In addition, RNA-seq was used to elucidate the molecular mechanism of root drought resistance. We identified 8588 differentially expressed genes related to drought tolerance in root, which were mainly enriched in oxidation-reduction process, carbohydrate metabolic process, apoplast, arginine and proline metabolism, and phenylpropanoid biosynthesis pathways. The expression levels of DEGs were consistent with physiological changes of ryegrass under drought stress. We found that genes related to sucrose and starch synthesis, root development, osmotic adjustment, ABA signal regulation and specifically up-regulated transcription factors such as WRKY41, WRKY51, ERF7, ERF109, ERF110, NAC43, NAC68, bHLH162 and bHLH148 in Chuansi No. 1 may be the reason for its higher drought tolerance. This study revealed the underlying physiological and molecular mechanisms of root response to drought stress in ryegrass and provided some new candidate genes for breeding rye drought tolerant varieties.


Assuntos
Secas , Lolium , Antioxidantes , Arginina , Carboidratos , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas , Lolium/genética , Melhoramento Vegetal , Prolina/genética , Amido , Sacarose , Fatores de Transcrição/genética , Água
12.
Food Microbiol ; 108: 104113, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36088120

RESUMO

Plants influence epiphytic bacterial associations but Salmonella enterica colonizes crop plants commensally, raising the possibility of human foodborne illness, but the factors that mediate human pathogen-plant associations remain understudied. We evaluated whether any changes in leaf tissue and surface metabolomes with kale (Brassica oleracea Acephala group) development and in response to drought modulated Salmonella leaf association. Untargeted phytochemical profiling (including primary and secondary metabolites) of kale leaf tissue extracts and leaf surface washes revealed distinct metabolite profiles that shifted with plant development. Metabolomes of juvenile plants also diverged in response to drought stress, an effect not noted in mature kale. Restricted watering in juvenile plants led to up-accumulation of 45 compounds in leaf tissue and 21 in leaf wash and the appearance of several unique peaks, with concomitant increases in phytochemical measurements. The antioxidant capacity and total flavonoid content were higher in mature than juvenile, regularly watered plant leaf extracts. Drought also elicited flavonoids and glucosinolates in juvenile plants. In mature plants, drought did not induce further prominent changes. Regularly watered juvenile kale provided a favorable substrate for inoculated Salmonella but the ability to support Salmonella declined with age and with drought stress. Salmonella growth was impaired in mature or water-stressed plant washes compared to controls and positive correlations were detected between Salmonella counts on leaves and in leaf washes. Moreover, Salmonella counts were inversely correlated with total flavonoids and phenolics in kale tissues from juvenile plants and regularly watered plants. Future studies should assess how changes in primary and secondary metabolites on the kale plant surface can modulate the Salmonella association. Regulated water restriction could be a strategy in controlled agriculture, with the dual purpose of enhancing health beneficial quality and food safety, especially when harvested at the baby kale stage.


Assuntos
Brassica , Salmonella enterica , Brassica/química , Secas , Flavonoides/análise , Flavonoides/metabolismo , Inocuidade dos Alimentos , Humanos , Metaboloma , Compostos Fitoquímicos , Salmonella enterica/metabolismo , Água/metabolismo
13.
Curr Microbiol ; 79(10): 308, 2022 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-36088515

RESUMO

The profile of endophytic bacteria in groundnut and their potential contribution to the reduction of drought stress are incompletely understood. Therefore, the current study is concentrated on examining the groundnut-culturable endophytic bacterial diversity, which has practical implications for reducing drought stress. Polyethylene glycol (PEG 6000) was used to identify the osmotic stress-tolerant bacterial isolates, and 51 strains were selected based on their tolerance. Fourteen potential bacterial strains with drought alleviation capacity and plant growth-promoting properties were selected and their identity was confirmed using 16S rRNA analysis. These isolates were positive for 1-aminocyclopropane-1-carboxylate deaminase, ammonia, minerals solubilization, and indole acetic acid. When applied to the groundnut seeds under water deficit conditions, the bacterial consortium (A. deltaense AMT1/Rhizobium sp. (N-Fixer) Caballeronia zhejiangensis BPT9 (PSB), Burkholderia dolosa BPT8 (KRB), and Bacillus safensis BPT6 (Drought-Mitigating Isolate)) increased the peanut germination by 91%. Soil application improved the aggregate formation. Further testing was carried out in the pot culture, where bacterial consortium improved the shoot length, root length, relative water content, chlorophyll content, nodule number, oil content, and kernel yield at 75% Water Holding capacity (WHC). Moreover, the treatment with bacterial consortia further stimulated the drought-protective mechanisms and resulted in higher efficiency of nitrogen, phosphorous, potassium uptake, electrolytes leakage, and soil enzymes such as dehydrogenase and alkaline phosphatase at 75% WHC. Microbial consortia inoculation controlled groundnut water absorption, photosynthetic performance, and stress metabolites, reducing drought-induced damage; hence, it is believed that endophytes have potential application in the improvement of yields of crops.


Assuntos
Secas , Solo , Arachis , Bactérias/genética , RNA Ribossômico 16S/genética , Água
14.
BMC Plant Biol ; 22(1): 428, 2022 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-36071408

RESUMO

BACKGROUND: Calmodulin-binding transcription activators (CAMTAs) are relatively conserved calmodulin-binding transcription factors widely found in eukaryotes and play important roles in plant growth and stress response. CAMTA transcription factors have been identified in several plant species, but the family members and functions have not yet been identified and analyzed in quinoa. RESULTS: In this study, we identified seven CAMTA genes across the whole quinoa genome and analyzed the expression patterns of CqCAMTAs in root and leaf tissues. Gene structure, protein domain, and phylogenetic analyses showed that the quinoa CAMTAs were structurally similar and clustered into the same three major groups as other plant CAMTAs. A large number of stress response-related cis-elements existed in the 2 kb promoter region upstream of the transcription start site of the CqCAMTA genes. qRT-PCR indicated that CqCAMTA genes were expressed differentially under PEG treatments in leaves, and responded to drought stress in leaves and roots. In particular, the CqCAMTA03 gene strongly responded to drought. The transient expression of CqCAMTA03-GFP fusion protein in the tobacco leaf showed that CqCAMTA03 was localized in the nucleus. In addition, transgenic Arabidopsis lines exhibited higher concentration levels of the antioxidant enzymes measured, including POD, SOD, and CAT, under drought conditions with very low levels of H2O2 and MDA. Moreover, relative water content and the degree of stomatal opening showed that the transgenic Arabidopsis lines were more tolerant of both stress factors as compared to their wild types. CONCLUSION: In this study, the structures and functions of the CAMTA family in quinoa were systematically explored. Many CAMTAs may play vital roles in the regulation of organ development, growth, and responses to drought stress. The results of the present study serve as a basis for future functional studies on the quinoa CAMTA family.


Assuntos
Arabidopsis , Secas , Arabidopsis/metabolismo , Calmodulina/metabolismo , Peróxido de Hidrogênio/metabolismo , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética
15.
Proc Natl Acad Sci U S A ; 119(37): e2116626119, 2022 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-36067321

RESUMO

Intact tropical rainforests have been exposed to severe droughts in recent decades, which may threaten their integrity, their ability to sequester carbon, and their capacity to provide shelter for biodiversity. However, their response to droughts remains uncertain due to limited high-quality, long-term observations covering extensive areas. Here, we examined how the upper canopy of intact tropical rainforests has responded to drought events globally and during the past 3 decades. By developing a long pantropical time series (1992 to 2018) of monthly radar satellite observations, we show that repeated droughts caused a sustained decline in radar signal in 93%, 84%, and 88% of intact tropical rainforests in the Americas, Africa, and Asia, respectively. Sudden decreases in radar signal were detected around the 1997-1998, 2005, 2010, and 2015 droughts in tropical Americas; 1999-2000, 2004-2005, 2010-2011, and 2015 droughts in tropical Africa; and 1997-1998, 2006, and 2015 droughts in tropical Asia. Rainforests showed similar low resistance (the ability to maintain predrought condition when drought occurs) to severe droughts across continents, but American rainforests consistently showed the lowest resilience (the ability to return to predrought condition after the drought event). Moreover, while the resistance of intact tropical rainforests to drought is decreasing, albeit weakly in tropical Africa and Asia, forest resilience has not increased significantly. Our results therefore suggest the capacity of intact rainforests to withstand future droughts is limited. This has negative implications for climate change mitigation through forest-based climate solutions and the associated pledges made by countries under the Paris Agreement.


Assuntos
Secas , Floresta Úmida , Mudança Climática , Árvores/fisiologia , Clima Tropical
16.
BMC Plant Biol ; 22(1): 439, 2022 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-36100908

RESUMO

BACKGROUND: Climatic warming is increasing regionally and globally, and results concerning warming and its consequent drought impacts have been reported extensively. However, due to a lack of quantitative analysis of warming severities, it is still unclear how warming and warming-induced drought influence leaf functional traits, particularly how the traits coordinate with each other to cope with climatic change. To address these uncertainties, we performed a field experiment with ambient, moderate and severe warming regimes in an arid ecosystem over 4 years. RESULTS: Severe warming significantly reduced the specific leaf area and net photosynthetic rate with a relatively stable change and even enhancement under moderate warming, especially showing species-specific performance. The current results largely indicate that a coordinated trade-off can exist between plant functional traits in plant communities in a dryland ecosystem under ambient temperature conditions, which is strongly amplified by moderate warming but diminished or even eliminated by severe warming. Based on the present findings and recent results in the relevant literature, we advance the ecological conceptual models (e.g., LES and CSR) in the response to climatic warming in arid grassland communities, where the few key species play a crucial role by balancing their functional performances to cope with environmental change. CONCLUSION: Our results highlight the importance of coordination and/or trade-off between leaf functional traits for understanding patterns of climatic change-induced vegetation degradation and suggest that the plant community composition in these drylands could be shifted under future climate change.


Assuntos
Ecossistema , Folhas de Planta , Mudança Climática , Secas , Folhas de Planta/fisiologia , Plantas
17.
Ying Yong Sheng Tai Xue Bao ; 33(9): 2331-2338, 2022 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-36131647

RESUMO

Two factors-two levels experiment (full light and shading, the irradiance in the shading was 30% of the full light; normal water and drought, where soil moisture was maintained at 75%-80% and 40%-45% of field capacity, respectively) was conducted to study the variation of light-induced stomatal dynamics, stomatal traits, whole plant growth and water use under shading and drought for the early succession stage species Betula platyphylla seedlings in the hilly area of the Loess Plateau. Results showed that shading significantly increased lag and response time by 0.8 and 1.8 times during stomatal opening, decreased response speed significantly by 82.2% and 65.0%, and response amplitude by 43.3% and 56.9% during stomatal opening and closing, respectively. Drought significantly reduced response amplitude by 43.9% during stomatal opening and response speed by 33.0% during stomatal closing. The interaction of shading and drought only affected lag time during stomatal opening. The response speed during stomatal closing was significantly positively correlated with stomatal density and stomatal index. There was no significant correlation between other stomatal dynamic parameters and stomatal anatomical structure. Response speed during stomatal closing was positively correlated with whole plant biomass and water consumption, and there was no correlation between stomatal dynamics parameters and water use efficiency. The results showed that the effects of shading and drought on light-induced stomatal dynamics were partly attributed to the alteration of stomata anatomical structure, and that the light-induced stomatal dynamic parameters could partly explain the alterations of B. platyphylla growth under different habitats.


Assuntos
Secas , Plântula , Betula , Folhas de Planta/fisiologia , Estômatos de Plantas/fisiologia , Plântula/fisiologia , Solo , Água
18.
Ying Yong Sheng Tai Xue Bao ; 33(9): 2388-2396, 2022 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-36131654

RESUMO

Chinese fir (Cunninghamia lanceolata) plantation is a dominant forest type and carbon sink in the subtropical region in China. An experiment with simulated nitrogen deposition (addition of 40 kg N·hm-2·a-1) and drought (50% of precipitation exclusion, PE) was established in Chinese fir plantation in 2018. Soil samples (0-15 cm) were collected in summer (July 2020) and winter (January 2021). Soil microbial biomass, colony forming units (CFUs) and carbon source utilization were determined through phospholipid fatty acids (PLFAs), plate count, and Biolog methods, respectively. The results showed significant seasonal variations of PLFAs-related microbial biomass and composition. Soil bacterial and fungal CFUs tended to be decreased by nitrogen addition or precipitation exclusion treatment, and bacterial CFUs were more sensitive to the two treatments than fungal CFUs. Soil microbial function (i.e. carbon source utilization) was not affected by nitrogen addition, but significantly decreased by precipitation exclusion. There was a significant positive correlation between bacterial CFUs and microbial function, indicating the crucial roles of culturable bacteria in microbial carbon transformation. Our results highlight the critical effects of nitrogen deposition and 50% reduced precipitation on microbes in topsoil of fir plantation, with implications for unraveling soil microbial ecological function of subtropical forest ecosystem under global changes in future.


Assuntos
Cunninghamia , Bactérias , Biomassa , Carbono/análise , China , Secas , Ecossistema , Ácidos Graxos , Nitrogênio/análise , Fosfolipídeos , Solo , Microbiologia do Solo
19.
Ying Yong Sheng Tai Xue Bao ; 33(9): 2457-2465, 2022 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-36131662

RESUMO

Meteorological disaster is one of the main factors restricting agriculture development in China. It is important to clarify the risk of summer maize agrometeorological disaster for disaster prevention and mitigation. Based on the natural disaster risk theory, we collected meteorological data and maize yield data from 1981 to 2018 in a typical area in the northern mountainous area of Sichuan Basin (Wangcang County). The main disaster-causing factors affecting summer maize production were determined. A comprehensive agro-meteorological disaster risk assessment model for summer maize was constructed in combination with the sensitivity of pregnant environment and vulnerability of disaster bearing to evaluate the agrometeorological disasters risk of summer maize production in the northern mountainous area of Sichuan Basin. The results showed that during the study period, high temperature in mature period, rainstorm in flowering period, rainstorm in mature period, continuous rain in filling period and drought in booting stage were the main agrometeorological disasters affecting the growth and development of summer maize. The agrometeorological disaster risk of maize generally distributed in a southwest-northeast pattern, with the distribution areas of high-risk and higher-risk areas accounting for half of the total area of Wangcang County. The high-risk areas were mainly located in the southwest of the county, which was basically consistent with the high-value areas of hazard-pregnant environment sensitivity. The low-risk areas were mostly concentrated in the western part of county territory, which were also low-risk areas of high temperature in mature period, rainstorm in mature period, and rainstorm in flowering period disasters.


Assuntos
Desastres , Zea mays , China , Desastres/prevenção & controle , Secas , Sistemas de Informação Geográfica , Medição de Risco
20.
PLoS One ; 17(9): e0273975, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36048864

RESUMO

Water shortages have always been the primary bottleneck for the healthy and sustainable development of the ecological environment on the Loess Plateau (LP). Proper water resource management requires knowledge of the spatiotemporal characteristics of precipitation frequency. This paper employed the gridded precipitation dataset obtained from the China Meteorological Data Service Centre to present a spatially explicit characterization of precipitation frequencies in tandem with their return periods on the LP based on the L-moment method. The 60% and 80% of the mean annual precipitation from 1981 to 2010 were synonymous with severe and moderate droughts, respectively. Droughts occurred more frequently in the northwest than in the southeast of the LP. Moreover, the frequencies of moderate drought showed a slight difference throughout the area, while those of severe droughts demonstrated considerable differences between the northwestern arid zone and the southeastern semi-humid zone. The maps associated with various return periods of precipitation deficits can be used to produce drought risk maps together with drought vulnerability maps. These findings could also provide useful information for drought management, water resource management and the development of food security policies.


Assuntos
Secas , Meteorologia , China , Água , Recursos Hídricos
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