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1.
Plant Physiol Biochem ; 159: 211-225, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33385704

RESUMO

Present investigation reports the role of calcium (Ca2+) and hydrogen sulfide (H2S) crosstalk associated with Vigna radiata seedlings subjected to K+ deficient conditions under short-term (24 h) and long-term (72 h) NaCl stress. Perusal of the data reveals that under short-term NaCl stress an initial decline in K+ level led to the elevation in Ca2+ and H2S levels along with improvement in antioxidant system and reduction in reactive oxygen species (ROS) production. Under long-term NaCl stress a further decline in K+ content was deleterious that led to a lower K+/Na+ ratio. This was followed by reduction in antioxidant system along with excessive accumulation of ROS and methylglyoxal content, and increased membrane damage. However, supplementation of the seedling roots with Ca2+ enhanced biosynthesis of H2S through enhancing cysteine pool. The present findings suggest that synergistic action of Ca2+ and H2S induced the activity of H+-ATPase that created H+ gradient which in turn induced Na+/H+ antiport system that accelerated K+ influx and Na+ efflux. All of these together contributed to a higher K+/Na+ ratio, activation of antioxidative defense system, and maintenance of redox homeostasis and membrane integrity in Ca2+-supplemented stressed seedlings. Role of Ca2+ and H2S in the regulation of Na+/H+ antiport system was validated by the use of sodium orthovanadate (plasma membrane H+-ATPase inhibitor), tetraethylammonium chloride (K+ channel blocker), and amiloride (Na+/H+ antiporter inhibitor). Application of Ca2+-chelator EGTA (ethylene glycol-bis(b-aminoethylether)-N,N,N',N'-tetraacetic acid) and H2S scavenger hypotaurine abolished the effect of Ca2+, suggesting the involvement of Ca2+ and H2S in the alleviation of NaCl stress. Moreover, use of EGTA and HT also substantiates the downstream functioning of H2S during Ca2+-mediated regulation of plant adaptive responses to NaCl stress. To sum up, present findings reveal the association of Ca2+ and H2S signaling in the regulation of ion homeostasis and antioxidant defense during K+-deficient NaCl stress.


Assuntos
Cálcio , Sulfeto de Hidrogênio , Raízes de Plantas , Vigna , Antioxidantes/metabolismo , Cálcio/metabolismo , Sulfeto de Hidrogênio/metabolismo , Transporte de Íons , Raízes de Plantas/fisiologia , Potássio/metabolismo , Estresse Salino/fisiologia , Cloreto de Sódio/farmacologia , Trocadores de Sódio-Hidrogênio/metabolismo , Vigna/fisiologia
2.
PLoS One ; 15(10): e0233481, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33001997

RESUMO

Pearl millet is a key cereal for food security in arid and semi-arid regions but its yield is increasingly threatened by water stress. Physiological mechanisms relating to conservation of soil water or increased water use efficiency can alleviate that stress. Aquaporins (AQP) are water channels that mediate root water transport, thereby influencing plant hydraulics, transpiration and soil water conservation. However, AQP remain largely uncharacterized in pearl millet. Here, we studied AQP function in root water transport in two pearl millet lines contrasting for water use efficiency (WUE). We observed that these lines also contrasted for root hydraulic conductivity (Lpr) and AQP contribution to Lpr. The line with lower WUE showed significantly higher AQP contribution to Lpr. To investigate AQP isoforms contributing to Lpr, we developed genomic approaches to first identify the entire AQP family in pearl millet and secondly, characterize the plasma membrane intrinsic proteins (PIP) gene expression profile. We identified and annotated 33 AQP genes in pearl millet, among which ten encoded PIP isoforms. PgPIP1-3 and PgPIP1-4 were significantly more expressed in the line showing lower WUE, higher Lpr and higher AQP contribution to Lpr. Overall, our study suggests that the PIP1 AQP family are the main regulators of Lpr in pearl millet and may possibly be associated with mechanisms associated to whole plant water use. This study paves the way for further investigations on AQP functions in pearl millet hydraulics and adaptation to environmental stresses.


Assuntos
Aquaporinas , Pennisetum , Raízes de Plantas/fisiologia , Adaptação Fisiológica , Aquaporinas/genética , Aquaporinas/metabolismo , Genes de Plantas , Genoma de Planta , Pennisetum/genética , Pennisetum/fisiologia , Estresse Fisiológico , Transcriptoma , Água/metabolismo
3.
Nat Commun ; 11(1): 5343, 2020 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-33093443

RESUMO

Plants transmit signals long distances, as evidenced in grafting experiments that create distinct rootstock-scion junctions. Noncoding small RNA is a signaling molecule that is graft transmissible, participating in RNA-directed DNA methylation; but the meiotic transmissibility of graft-mediated epigenetic changes remains unclear. Here, we exploit the MSH1 system in Arabidopsis and tomato to introduce rootstock epigenetic variation to grafting experiments. Introducing mutations dcl2, dcl3 and dcl4 to the msh1 rootstock disrupts siRNA production and reveals RdDM targets of methylation repatterning. Progeny from grafting experiments show enhanced growth vigor relative to controls. This heritable enhancement-through-grafting phenotype is RdDM-dependent, involving 1380 differentially methylated genes, many within auxin-related gene pathways. Growth vigor is associated with robust root growth of msh1 graft progeny, a phenotype associated with auxin transport based on inhibitor assays. Large-scale field experiments show msh1 grafting effects on tomato plant performance, heritable over five generations, demonstrating the agricultural potential of epigenetic variation.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Lycopersicon esculentum/genética , Proteína MutS de Ligação de DNA com Erro de Pareamento/genética , Proteínas de Plantas/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Proteínas de Arabidopsis/fisiologia , Metilação de DNA , Epigênese Genética , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/fisiologia , Proteína MutS de Ligação de DNA com Erro de Pareamento/fisiologia , Mutação , Fenótipo , Melhoramento Vegetal , Proteínas de Plantas/fisiologia , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/fisiologia , Plantas Geneticamente Modificadas , RNA de Plantas/genética , RNA de Plantas/metabolismo , RNA Interferente Pequeno/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
4.
PLoS One ; 15(9): e0238362, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32877452

RESUMO

Water and nutrient absorption from soil by crops mainly depend on the morphological traits and distribution of the crop roots. Dense planting with reduced nitrogen is a sustainable strategy for improving grain yield and nitrogen use efficiency. However, there is little information on the effects of dense planting with reduced nitrogen on direct-seeded inbred rice. Two-year field experiments were conducted with minirhizotron techniques to characterize the root morphological traits and distributions under different nitrogen application rates and sowing densities in two representative inbred rice varieties, Huanghuazhan (HHZ) and Yuenongsimiao (YNSM), grown under three nitrogen application rates (N0: 0 kg ha-1, LN: 135 kg ha-1, HN: 180 kg ha-1) and two sowing densities (LD: 18.75 kg ha-1, HD: 22.5 kg ha-1). Our study showed that dense planting with low nitrogen improved grain yield partly due to the increased panicle number. The higher sowing density with low nitrogen significantly affected the total root number (TRN), total root length (TRL), total root surface area (TRSA), and total root volume (TRV). There was a significant positive correlation between grain yield and TRL in the 10-20-cm soil layer (P < 0.05). The root morphological indexes were positively correlated with dry matter accumulation (P < 0.05) and negatively correlated with nitrogen content (P < 0.05) at the maturity stage. This study showed that a high sowing density with low nitrogen application can improve root morphology and distribution and increase grain yield and nitrogen use efficiency in direct-seeded inbred rice.


Assuntos
Nitrogênio/farmacologia , Oryza/fisiologia , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/fisiologia , Sementes/fisiologia , Solo/química , Água/química , Oryza/efeitos dos fármacos , Fenótipo , Raízes de Plantas/efeitos dos fármacos , Estações do Ano , Sementes/efeitos dos fármacos
5.
PLoS One ; 15(9): e0239075, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32941470

RESUMO

Iron (Fe) deficiency is a common challenge in crop production. Screening and research of Fe-efficient cultivars could alleviate plant stress and increase crop yields in Fe-deficient soils. In the present study, we conducted two hydroponic culture experiments with a control (100 µmol/L Fe3+-EDTA) and low Fe treatment (10 µmol/L Fe3+-EDTA) to study the morphological and physiological mechanisms of response to low Fe stress in maize hybrids seedlings. In the first experiment, we investigated 32 major maize hybrids in Southwest China. We found that six of them, including Zhenghong 2 (ZH 2), were Fe-efficient. Fifteen other cultivars, such as Chuandan 418 (CD 418), were Fe-inefficient. In the second experiment, we investigated the Fe-efficient ZH 2 and Fe-inefficient CD 418 cultivars and found that low Fe stress resulted in significant decreases in root volume, root length, number of root tips, root surface area, and root dry weight, and increased root to shoot ratio, average root diameter, and Fe-dissolution ability per mass of roots in both maize cultivars. However, the increase in Fe-dissolution ability per mass of roots in ZH 2 was higher than that in CD 418, whereas for the other measurements, the low Fe stress-induced changes in ZH 2 were less pronounced than in CD 418. Therefore, under low Fe stress, the above-mentioned growth factors in ZH 2 were higher by 54.84%, 121.46%, 107.67%, 83.96%, 140.00%, and 18.16%, respectively, than those in CD 418. In addition, leaf area, chlorophyll content, net photosynthetic rate, soluble protein content, and Catalase (CAT) and Peroxidase (POD) activities in ZH 2 were higher by 274.95%, 113.95%, 223.60%, 56.04%, 17.01% and 21.13% than those in CD 418. Therefore, compared with the Fe-inefficient cultivar (CD 418), the Fe-efficient cultivar (ZH 2) had a more developed root system and greater Fe absorption capacity per mass of roots under low iron stress, promoted the efficient absorption of Fe, maintained a higher photosynthetic area and photosynthetic rate, thereby facilitating the accumulation of photosynthetic products. Moreover, higher soluble protein content and activities of CAT and POD permitted high osmotic regulation and scavenging ability, which is an important physiological mechanism for ZH 2 adaptation to low Fe stress.


Assuntos
Raízes de Plantas/fisiologia , Plântula/fisiologia , Zea mays/fisiologia , Ferro/metabolismo , Fotossíntese , Raízes de Plantas/anatomia & histologia , Plântula/anatomia & histologia , Estresse Fisiológico , Zea mays/anatomia & histologia
6.
Gene ; 758: 144954, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32683079

RESUMO

Teosinte branched1/cycloidea/proliferating cell factor1 (TCP) is a plant-specific protein family member involved in plant growth and development. However, the functions of most members of the cotton TCP family are unknown. In this study, the GbTCP5 gene encodes a sea-island cotton class II TCP CIN subclass transcription factor. The GbTCP5 transcription factor is located in the nucleus, has transcriptional activation activity, and can bind to TCP II cis-acting elements. GbTCP5 was widely expressed in tissues with the highest transcript level in the calyx. GbTCP5 is expressed at different developmental stages of the fiber and has significantly high transcriptional level expression in the fibers at 20, 30 and 35 days post anthesis (DPA). Heterologous overexpression of the GbTCP5 gene increased root hair length, root hair and stem trichome density, and stem lignin content in transgenic Arabidopsis compared to the wild type (WT). GbTCP5 binds the promoters of the GL3, EGL3, CPC, MYB46, LBD30, CesA4, VND7, CCOMT1, and CAD5 genes to upregulate their expression. Moreover, the homologous genes of these genes are expressed in the fibers of different developmental stages of the sea-island cotton fiber. These results indicate that GbTCP5 regulates root hair development and secondary wall formation in Arabidopsis and may be a candidate gene for improving cotton fiber quality.


Assuntos
Arabidopsis/genética , Gossypium/genética , Lignina/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Fatores de Transcrição/genética , Tricomas/crescimento & desenvolvimento , Arabidopsis/crescimento & desenvolvimento , Fibra de Algodão/análise , Proteínas de Ligação a DNA/genética , Raízes de Plantas/fisiologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Regiões Promotoras Genéticas/genética , Ativação Transcricional/genética
7.
PLoS One ; 15(7): e0236317, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32702002

RESUMO

Heterodera avenae, as an obligate endoparasite, causes severe yield loss in wheat (Triticum aestivum). Investigation on the mechanisms how H. avenae perceives wheat roots is limited. Here, the attractiveness of root exudates from eight plant genotypes to H. avenae were evaluated on agar plates. Results showed that the attraction of H. avenae to the root exudates from the non-host Brachypodium distachyon variety Bd21-3 was the highest, approximately 50 infective second-stage juveniles (J2s) per plate, followed by that from three H. avenae-susceptible wheat varieties, Zhengmai9023, Yanmai84 and Xiangmai25, as well as the resistant one of Xinyuan958, whereas the lowest attractive activity was observed in the two H. avenae-resistant wheat varieties, Xianmai20 (approximately 12 J2s/plate) and Liangxing66 (approximately 11 J2s/plate). Then Bd21-3, Zhengmai9023 and Heng4399 were selected for further assays as their different attractiveness and resistance to H. avenae, and attractants for H. avenae in their root exudates were characterized to be heat-labile and low-molecular compounds (LM) by behavioral bioassay. Based on these properties of the attractants, a principle of identifying attractants for H. avenae was set up. Then LM of six root exudates from the three plants with and without heating were separated and analyzed by HPLC-MS. Finally, dihydroxyacetone (DHA), methylprednisolone succinate, embelin and diethylpropionin in the root exudates were identified to be putative attractants for H. avenae according to the principle, and the attraction of DHA to H. avenae was validated by behavioral bioassay on agar. Our study enhances the recognition to the orientation mechanism of H. avenae towards wheat roots.


Assuntos
Di-Hidroxiacetona/química , Doenças das Plantas/parasitologia , Raízes de Plantas/química , Triticum/química , Animais , Brachypodium/genética , Brachypodium/parasitologia , Di-Hidroxiacetona/fisiologia , Resistência à Doença/genética , Resistência à Doença/fisiologia , Genótipo , Doenças das Plantas/genética , Raízes de Plantas/genética , Raízes de Plantas/parasitologia , Raízes de Plantas/fisiologia , Triticum/genética , Triticum/parasitologia , Triticum/fisiologia , Tylenchoidea/genética , Tylenchoidea/patogenicidade
8.
Plant Physiol Biochem ; 153: 81-91, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32485616

RESUMO

Drought stress influences the growth of plants and thus grafting has been widely used to improve tolerance to abiotic stresses. Poplars possess sex-specific responses to drought stress, but how male or female rootstock affect the grafted plant is little known. To explore the mechanisms underlying changes in drought tolerance caused by grafting, we investigated the changes in growth, leaf traits, gas exchange and antioxidant enzyme activities of reciprocally grafted seedlings between Populus euramericana cv. "Nanlin895" (NL-895) (female) and Populus deltiodes cv."3412" (NL-3412) (male) under water deficit stress with 30% field capacity for 30 d. Results showed that drought stress affected adversely growth, morphological, and physiological characteristics in all seedlings studied. Grafted seedlings with male roots can effectively alleviated the inhibition of growth induced by drought stress, as shown by higher WUE, activities of SOD, POD and CAT, and lower levels of lipid peroxidation. Male seedlings with female roots were found to be less tolerance to drought than non-grafted male clones and female scions with male roots, but more tolerance than non-grafted female clones. This results suggested that drought tolerance of grafted seedlings is primarily caused by the rootstock, although the scion also affects the grafted plant. Thus, paying attention on the root genotype can provide an important means of improving the drought tolerance of poplars.


Assuntos
Secas , Raízes de Plantas/fisiologia , Populus/fisiologia , Estresse Fisiológico , Genótipo , Folhas de Planta , Raízes de Plantas/classificação , Populus/classificação , Plântula
9.
Appl Environ Microbiol ; 86(17)2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32591378

RESUMO

The number of sustainable agriculture techniques to improve pest management and environmental safety is rising, as biological control agents are used to enhance disease resistance and abiotic stress tolerance in crops. Here, we investigated the capacity of the Photorhabdus luminescens secondary variant to react to plant root exudates and their behavior toward microorganisms in the rhizosphere. P. luminescens is known to live in symbiosis with entomopathogenic nematodes (EPNs) and to be highly pathogenic toward insects. The P. luminescens-EPN relationship has been widely studied, and this combination has been used as a biological control agent; however, not much attention has been paid to the putative lifestyle of P. luminescens in the rhizosphere. We performed transcriptome analysis to show how P. luminescens responds to plant root exudates. The analysis highlighted genes involved in chitin degradation, biofilm regulation, formation of flagella, and type VI secretion system. Furthermore, we provide evidence that P. luminescens can inhibit growth of phytopathogenic fungi. Finally, we demonstrated a specific interaction of P. luminescens with plant roots. Understanding the role and the function of this bacterium in the rhizosphere might accelerate the progress in biocontrol manipulation and elucidate the peculiar mechanisms adopted by plant growth-promoting rhizobacteria in plant root interactions.IMPORTANCE Insect-pathogenic Photorhabdus luminescens bacteria are widely used in biocontrol strategies against pests. Very little is known about the life of these bacteria in the rhizosphere. Here, we show that P. luminescens can specifically react to and interact with plant roots. Understanding the adaptation of P. luminescens in the rhizosphere is highly important for the biotechnological application of entomopathogenic bacteria and could improve future sustainable pest management in agriculture.


Assuntos
Quimiotaxia , Photorhabdus/fisiologia , Raízes de Plantas/microbiologia , Raízes de Plantas/fisiologia , Rizosfera , Agentes de Controle Biológico , Exsudatos e Transudatos/química , Fungos/fisiologia , Perfilação da Expressão Gênica , Genes Bacterianos , Photorhabdus/genética , RNA-Seq
10.
Sci Rep ; 10(1): 10201, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32576948

RESUMO

Waterlogging stress is a common limiting factor for winter rapeseed, which greatly affects the growth and potential production. The present study was conducted to investigate the effects of waterlogging with different durations (0day (D0), 6days (D6) and 9days (D9)) and supplemental nitrogen fertilization (N1, 0 kg ha-1; N2, 30 kg ha-1; N3, 60 kg ha-1 and N4, 90 kg ha-1) on the physiological characteristics, dry matter and nitrogen accumulation in winter rapeseed (Chuanyou36). The results showed that the supplementary application of nitrogen fertilizer could effectively improve the physiological indexes of winter rapeseed in both pot and field experiments. The supplemental nitrogen increased the chlorophyll content in leaves, enhanced the activities of SOD, CAT, and POD, and decreased the MDA content in leaves and roots of rapeseed. The chlorophyll contents, the antioxidant enzyme activity of leaves and roots significantly increased under D6N3 and D9N4 conditions in both (pot and field) experiments. However, MDA contents significantly decreased compared with waterlogging without nitrogen application. Moreover, the application of nitrogen fertilizer after waterlogging increased the accumulation of dry matter and nitrogen in rapeseed at different growth stages. Therefore, waterlogging stress significantly inhibited the growth and development of rapeseed, but the application of nitrogen fertilizer could effectively reduce the damage of waterlogging. The N-induced increase in waterlogging tolerance of rapeseed might be attributed to the strong antioxidant defense system, maintenance of photosynthetic pigments and the nutrient balance.


Assuntos
Brassica napus/metabolismo , Brassica napus/fisiologia , Nitrogênio/metabolismo , Estresse Fisiológico/fisiologia , Água/metabolismo , Clorofila/metabolismo , Fertilizantes , Fotossíntese/fisiologia , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Estações do Ano
11.
Proc Natl Acad Sci U S A ; 117(26): 15322-15331, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32541049

RESUMO

Wound healing in plant tissues, consisting of rigid cell wall-encapsulated cells, represents a considerable challenge and occurs through largely unknown mechanisms distinct from those in animals. Owing to their inability to migrate, plant cells rely on targeted cell division and expansion to regenerate wounds. Strict coordination of these wound-induced responses is essential to ensure efficient, spatially restricted wound healing. Single-cell tracking by live imaging allowed us to gain mechanistic insight into the wound perception and coordination of wound responses after laser-based wounding in Arabidopsis root. We revealed a crucial contribution of the collapse of damaged cells in wound perception and detected an auxin increase specific to cells immediately adjacent to the wound. This localized auxin increase balances wound-induced cell expansion and restorative division rates in a dose-dependent manner, leading to tumorous overproliferation when the canonical TIR1 auxin signaling is disrupted. Auxin and wound-induced turgor pressure changes together also spatially define the activation of key components of regeneration, such as the transcription regulator ERF115. Our observations suggest that the wound signaling involves the sensing of collapse of damaged cells and a local auxin signaling activation to coordinate the downstream transcriptional responses in the immediate wound vicinity.


Assuntos
Arabidopsis/fisiologia , Ácidos Indolacéticos/metabolismo , Células Vegetais/fisiologia , Raízes de Plantas/fisiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Divisão Celular , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ácidos Indolacéticos/antagonistas & inibidores , Cinurenina/farmacologia , Lasers , Ftalimidas/farmacologia , Células Vegetais/efeitos dos fármacos , Regeneração/efeitos dos fármacos , Regeneração/fisiologia , Transdução de Sinais/fisiologia , Triazóis/farmacologia
12.
J Plant Physiol ; 249: 153180, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32422486

RESUMO

Several Lotus species are perennial forage legumes which tolerate waterlogging, but knowledge of responses to partial or complete shoot submergence is scant. We evaluated the responses of 15 Lotus accessions to partial and complete shoot submergence and variations in traits associated with tolerance and recovery after de-submergence. Accessions of Lotus tenuis, L. corniculatus, L. pedunculatus and L. japonicus were raised for 43 d and then subjected to aerated root zone (control), deoxygenated stagnant root zone with shoots in air (stagnant), stagnant root zone with partial (75 %) and complete submergence of shoots, for 7 d. The recovery ability from complete submergence was also assessed. We found inter- and intra-specific variations in the stem extension responses (i.e. promoted or restricted compared to controls) depending on water depth. Eight of 15 accessions promoted the stem extension when in partial submergence, while three of those eight (all L. tenuis accessions) had a restricted stem extension when under complete submergence. Two accessions (belonging to L. corniculatus and L. penduculatus species) also promoted the stem extension under complete submergence. The accessions that attained better recovery in terms of leaves produced after de-submergence, were those that had high leaf and root sugar concentration at de-submergence, and high thickness and persistence of gas films on leaves during submergence (all L. tenuis accessions). We conclude that all Lotus accessions were able to tolerate 7 d of partial and complete shoot submergence, despite adopting different stem extension responses.


Assuntos
Lotus/fisiologia , Brotos de Planta/fisiologia , Imersão , Lotus/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/fisiologia , Brotos de Planta/crescimento & desenvolvimento , Especificidade da Espécie
13.
PLoS One ; 15(5): e0233878, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32470094

RESUMO

The present study aimed to investigate the effects of arbuscular mycorrhizal (AM) fungal communities originating from organic and conventional agriculture on wheat growth and yield. Six different spring wheat cultivars released in different years in north and central European countries were considered. We hypothesised that AM fungal inoculum collected from organic agricultural fields would elicit a greater positive growth response than inoculum collected from conventional agricultural fields; and that older cultivars, which were developed under conditions of low fertilizer input, would exhibit overall greater growth responses to the presence of AM fungi, compared with more recent cultivars, and that AM fungal inoculum from conventional fields might have the most beneficial effect on the growth and yield of recent cultivars. The results showed that the overall effects on the growth and yield of spring wheat grown with organic and conventional AM fungal inocula did not differ greatly. However, the inoculation growth response, showing the difference of the effects of organic and conventional inocula, varied between particular wheat cultivars. Inoculation growth response of the cultivar Pikker (released in 1959) was the most positive, while that of the cultivar Arabella (released in 2012) was the most negative. The use of AM fungal inoculum from organic fields resulted in slightly taller plant individuals. Pikker showed relatively higher yield and stronger growth when the organic AM fungal inoculum was used. Arabella exhibited relatively lower yield and weaker growth when the organic inoculum was used. Whether the positive response of Pikker to Estonian organic inoculation reflects adaptation to the locally occurring AM fungal community needs to be established by further studies of the communities of AM fungi colonizing wheat roots.


Assuntos
Fazendas , Micorrizas/fisiologia , Agricultura Orgânica , Triticum/crescimento & desenvolvimento , Triticum/microbiologia , Raízes de Plantas/fisiologia , Brotos de Planta/fisiologia , Solo , Microbiologia do Solo , Triticum/anatomia & histologia
14.
Ecotoxicology ; 29(6): 691-697, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32472470

RESUMO

A short term pot trail was employed to evaluate the exposure of mixed heavy metals (Cu, Pb and Zn) on growth, radial oxygen loss (ROL) and root anatomy in Bruguiera gymnorrhiza. The possible function of BgC4H, a cytochrome P450 gene, on root lignification was also discussed. The exposures of mixed Cu, Pb and Zn directly reduce O2 leakage at root surface. The reduced ROL inhibited by heavy metals was mainly ascribed by the changes in root anatomical features, such as decreased root porosity together with increased lignification within the exodermis. BgC4H was found to be up-regulated after 0.5-day metal exposure, and remained higher transcript levels within 3-day metal exposure when compared to control roots. Besides, the inhibited photosynthesis may also result in less oxygen can be transported to the underground roots. In summary, the mangrove B. gymnorrhiza appeared to react to external mixed metal contaminants by developing a lignified and impermeable exodermis, and such a root barrier induced by mixed Cu, Pb and Zn appeared to be an adaptive response to block metal ions enters into the roots.


Assuntos
Metais Pesados/toxicidade , Oxigênio/metabolismo , Raízes de Plantas/efeitos dos fármacos , Rhizophoraceae , Poluentes Químicos da Água/toxicidade , Áreas Alagadas , Cobre , Chumbo , Raízes de Plantas/fisiologia , Zinco
15.
Ecotoxicology ; 29(6): 684-690, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32394359

RESUMO

Tidal flooding can directly result in oxygen (O2) shortage, however the functions of root aeration in flooding tolerance and O2 dynamics within mangroves are still poorly understood. Thus, in this study, the correlations among waterlogging tolerance, root porosity and O2 movement within the plants were investigated using two mangrove species (Aegiceras corniculatum and Bruguiera gymnorrhiza) and a semi-mangrove Heritiera littoralis. Based on the present data, the species A. corniculatum and B. gymnorrhiza, which possessed higher root porosity, exhibited higher waterlogging tolerance, while H. littoralis is intolerant. Increased root porosity, leaf stoma, and total ROL were observed in the roots of A. corniculatum and B. gymnorrhiza growing in stagnant solution when compared to respective aerated controls. As for ROL spatial pattern along roots, external anaerobic condition could promote ROL from apical root regions but reduce ROL from basal roots, leading to a 'tighter barrier'. In summary, the present study indicated that the plants (e.g., A. corniculatum and B. gymnorrhiza) prioritized to ensure O2 diffusion towards root tips under waterlogging by increasing aerenchyma formation and reducing O2 leakage at basal root regions.


Assuntos
Primulaceae , Rhizophoraceae , Áreas Alagadas , Eutrofização , Oxigênio/metabolismo , Raízes de Plantas/fisiologia
16.
Sci Rep ; 10(1): 6746, 2020 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-32317769

RESUMO

With the increase in iron/steel production, the higher volume of by-products (slag) generated necessitates its efficient recycling. Because the Linz-Donawitz (LD) slag is rich in silicon (Si) and other fertilizer components, we aim to evaluate the impact of the LD slag amendment on soil quality (by measuring soil physicochemical and biological properties), plant nutrient uptake, and strengthens correlations between nutrient uptake and soil bacterial communities. We used 16 S rRNA illumine sequencing to study soil bacterial community and APIZYM assay to study soil enzymes involved in C, N, and P cycling. The LD slag was applied at 2 Mg ha-1 to Japonica and Indica rice cultivated under flooded conditions. The LD slag amendment significantly improved soil pH, plant photosynthesis, soil nutrient availability, and the crop yield, irrespective of cultivars. It significantly increased N, P, and Si uptake of rice straw. The slag amendment enhanced soil microbial biomass, soil enzyme activities and enriched certain bacterial taxa featuring copiotrophic lifestyles and having the potential role for ecosystem services provided to the benefit of the plant. The study evidenced that the short-term LD slag amendment in rice cropping systems is useful to improve soil physicochemical and biological status, and the crop yield.


Assuntos
Fertilizantes/análise , Consórcios Microbianos/efeitos dos fármacos , Oryza/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Resíduos/análise , Actinobacteria/classificação , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Alphaproteobacteria/classificação , Alphaproteobacteria/genética , Alphaproteobacteria/isolamento & purificação , Betaproteobacteria/classificação , Betaproteobacteria/genética , Betaproteobacteria/isolamento & purificação , Ciclo do Carbono/fisiologia , Deltaproteobacteria/classificação , Deltaproteobacteria/genética , Deltaproteobacteria/isolamento & purificação , Firmicutes/classificação , Firmicutes/genética , Firmicutes/isolamento & purificação , Gammaproteobacteria/classificação , Gammaproteobacteria/genética , Gammaproteobacteria/isolamento & purificação , Humanos , Concentração de Íons de Hidrogênio , Ferro/metabolismo , Ferro/farmacologia , Metalurgia/métodos , Consórcios Microbianos/fisiologia , Ciclo do Nitrogênio/fisiologia , Oryza/microbiologia , Oryza/fisiologia , Fósforo/fisiologia , Fotossíntese/fisiologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/microbiologia , Raízes de Plantas/fisiologia , RNA Ribossômico 16S/genética , Silício/metabolismo , Silício/farmacologia , Solo/química , Microbiologia do Solo , Aço/química
17.
Sci Rep ; 10(1): 5819, 2020 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-32242034

RESUMO

Climatic change is pointed as one of the major challenges for global food security. Based on current models of climate change, reduction in precipitations and in turn, increase in the soil salinity will be a sharp constraint for crops productivity worldwide. In this context, root fungi appear as a new strategy to improve plant ecophysiological performance and crop yield under abiotic stress. In this study, we evaluated the impact of the two fungal endophytes Penicillium brevicompactum and P. chrysogenum isolated from Antarctic plants on nutrients and Na+ contents, net photosynthesis, water use efficiency, yield and survival in tomato and lettuce, facing salinity stress conditions. Inoculation of plant roots with fungal endophytes resulted in greater fresh and dry biomass production, and an enhanced survival rate under salt conditions. Inoculation of plants with the fungal endophytes was related with a higher up/down-regulation of ion homeostasis by enhanced expression of the NHX1 gene. The two endophytes diminished the effects of salt stress in tomato and lettuce, provoked a higher efficiency in photosynthetic energy production and an improved sequestration of Na+ in vacuoles is suggested by the upregulating of the expression of vacuolar NHX1 Na+/H+ antiporters. Promoting plant-beneficial interactions with root symbionts appears to be an environmentally friendly strategy to mitigate the impact of climate change variables on crop production.


Assuntos
Produtos Agrícolas/metabolismo , Produtos Agrícolas/fisiologia , Endófitos/fisiologia , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Estresse Salino/fisiologia , Sódio/metabolismo , Regiões Antárticas , Biomassa , Mudança Climática , Produtos Agrícolas/microbiologia , Regulação para Baixo/fisiologia , Homeostase/fisiologia , Íons/metabolismo , Alface/metabolismo , Alface/microbiologia , Alface/fisiologia , Lycopersicon esculentum/metabolismo , Lycopersicon esculentum/microbiologia , Lycopersicon esculentum/fisiologia , Penicillium chrysogenum/fisiologia , Fotossíntese/fisiologia , Raízes de Plantas/microbiologia , Salinidade , Trocadores de Sódio-Hidrogênio/metabolismo , Solo , Estresse Fisiológico/fisiologia , Taxa de Sobrevida , Regulação para Cima/fisiologia , Água/metabolismo
18.
Nat Commun ; 11(1): 1766, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32286301

RESUMO

Arctic plant growth is predominantly nitrogen (N) limited. This limitation is generally attributed to slow soil microbial processes due to low temperatures. Here, we show that arctic plant-soil N cycling is also substantially constrained by the lack of larger detritivores (earthworms) able to mineralize and physically translocate litter and soil organic matter. These new functions provided by earthworms increased shrub and grass N concentration in our common garden experiment. Earthworm activity also increased either the height or number of floral shoots, while enhancing fine root production and vegetation greenness in heath and meadow communities to a level that exceeded the inherent differences between these two common arctic plant communities. Moreover, these worming effects on plant N and greening exceeded reported effects of warming, herbivory and nutrient addition, suggesting that human spreading of earthworms may lead to substantial changes in the structure and function of arctic ecosystems.


Assuntos
Nitrogênio/metabolismo , Oligoquetos/fisiologia , Plantas/metabolismo , Animais , Regiões Árticas , Ecossistema , Raízes de Plantas/fisiologia , Brotos de Planta/fisiologia , Poaceae
19.
Ecotoxicol Environ Saf ; 196: 110545, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32276162

RESUMO

The relationship between the chemical forms of Cu2+ and Cd2+ adsorbed on the roots of different wheat cultivars and their phytotoxic effects on the plants were investigated. The wheat varieties Dunmaiwang (DMW), Tekang 6 (TK6), Zhongmai895 (ZM895), and Chaojixiaomai (AK68) were used. The zeta potentials of wheat roots, measured by the streaming potential method, were used to characterize root charge properties. Results indicated that the changes in zeta potential at pH 4.01-6.61 were 14.7, 15.53, 13.01, and 12.06 mV for ZM895, AK68, DMW, and TK6, respectively. The negative charge and functional groups on ZM895 and AK68 roots were greater than on DMW and TK6 roots, which led to more exchangeable and complexed Cu2+ and Cd2+ on ZM895 and AK68 roots and increased Cu2+ and Cd2+ toxicity compared to DMW and TK6. Coexisting cations, such as Ca2+, Mg2+, K+, and NH4+, alleviated Cu2+ and Cd2+ toxicity to wheat roots through competition for adsorption sites on the roots, which decreased exchangeable and complexed Cu2+ and Cd2+ on wheat roots. The Ca2+ and Mg2+ were most effective in alleviating heavy metal toxicity and they decreased exchangeable Cu2+ on AK68 roots by 39.14% and 47.82%, and exchangeable Cd2+ by 8.51% and 28.23%, respectively.


Assuntos
Cádmio/toxicidade , Cobre/toxicidade , Poluentes do Solo/toxicidade , Triticum/efeitos dos fármacos , Adsorção , Cádmio/química , Cádmio/farmacocinética , Cátions , Cobre/química , Cobre/farmacocinética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Poluentes do Solo/química , Poluentes do Solo/farmacocinética , Triticum/metabolismo , Triticum/fisiologia
20.
Int J Mol Sci ; 21(5)2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32155833

RESUMO

Modified gibberellin (GA) signaling leads to semi-dwarfism with low nitrogen (N) use efficiency (NUE) in crops. An understanding of GA-mediated N uptake is essential for the development of crops with improved NUE. The function of GA in modulating N uptake capacity and nitrate (NO3-) transporters (NRTs) was analyzed in the GA synthesis-deficient mutant zmga3ox grown under low (LN) and sufficient (SN) N conditions. LN significantly suppressed the production of GA1, GA3, and GA4, and the zmga3ox plants showed more sensitivity in shoots as well as LN stress. Moreover, the higher anthocyanin accumulation and the decrease of chlorophyll content were also recorded. The net NO3- fluxes and 15N content were decreased in zmga3ox plants under both LN and SN conditions. Exogenous GA3 could restore the NO3- uptake in zmga3ox plants, but uniconazole repressed NO3- uptake. Moreover, the transcript levels of ZmNRT2.1/2.2 were downregulated in zmga3ox plants, while the GA3 application enhanced the expression level. Furthermore, the RNA-seq analyses identified several transcription factors that are involved in the GA-mediated transcriptional operation of NRTs related genes. These findings revealed that GAs influenced N uptake involved in the transcriptional regulation of NRTs and physiological responses in maize responding to nitrogen supply.


Assuntos
Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Giberelinas/farmacologia , Nitrogênio/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/fisiologia , Zea mays/fisiologia , Transporte Biológico , Fenótipo , Reguladores de Crescimento de Planta/farmacologia , Proteínas de Plantas/genética , Raízes de Plantas/efeitos dos fármacos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Zea mays/efeitos dos fármacos , Zea mays/metabolismo
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