Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Front Plant Sci ; 12: 740492, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34777421

RESUMO

Improved water use efficiency (WUE) promotes plant survival and crop yield under water deficit conditions. Although the plant-specific HD-Zip I transcription factors have important roles in plant adaptation to various abiotic stresses, including water deficit, their functions in regulating WUE of apple (Malus domestica) are poorly understood. We characterized the role of MdHB-7 in WUE regulation by subjecting MdHB-7 transgenic plants to long-term moderate soil water deficit. The long-term WUE (WUEL) of transgenic apple plants with MdHB-7 overexpression or MdHB-7 RNA interference (RNAi) differed significantly from that of control plants. Upregulation of MdHB-7 caused reduced stomatal density, whereas the suppression of MdHB-7 increased stomatal density under both normal and long-term moderate soil water deficit conditions. Moderate reduction in stomatal density helped to improve the WUE of MdHB-7 overexpression transgenic plants, especially under water deficit conditions. MdHB-7 overexpression plants maintained high rates of photosynthesis that were conducive to the accumulation of biomass and the improvement of WUEL. MdHB-7 overexpression also alleviated the inhibition of root growth caused by long-term moderate soil water deficit and improved root vitality and hydraulic conductivity, which were essential for improving plant WUEL. By contrast, MdHB-7 RNA interference reduced the WUEL of transgenic plants by inhibiting these factors under normal and long-term moderate soil water deficit conditions. Taken together, our results provide solid evidence for a crucial role of MdHB-7 in the regulation of apple WUEL and provide new insights for improving the WUE of apple plants under moderate soil water deficit.

2.
Plant Sci ; 312: 111052, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34620447

RESUMO

Drought occurrence seriously affects the productivity and quality of apple crop worldwide. Autophagy, a conserved process for the degradation and recycling of unwanted cellular components, is considered to positively regulate the tolerance of various abiotic stresses in plants. In the current study, we isolated two ATG5 homologs genes, namely, MdATG5a and MdATG5b, from apple, demonstrating their responsiveness to drought and oxidative stresses. In addition to having the same cellular localization in the nucleus and cytoplasm, both MdATG5a and MdATG5b could interact with MdATG12. Transgenic apple plants overexpressing MdATG5a exhibited an improved drought tolerance, as indicated by less drought-related damage and higher photosynthetic capacities compared to wild-type (WT) plants under drought stress. The overexpression of MdATG5a improved antioxidant defenses in apple when exposed to drought via elevating both antioxidant enzyme activities and the levels of beneficial antioxidants. Furthermore, under drought stress, the overexpression of MdATG5a promoted the mobilization of starch to accumulate greater levels of soluble sugars, contributing to osmotic adjustments and supporting carbon skeletons for proline synthesis. Such changes in physiological responses may be associated with increased autophagic activities in the transgenic plants upon exposure to drought. Our results demonstrate that MdATG5a-mediated autophagy enhances drought tolerance of apple plants via improving antioxidant defenses and metabolic adjustments.


Assuntos
Antioxidantes/metabolismo , Desidratação/genética , Desidratação/fisiopatologia , Secas , Malus/genética , Malus/fisiologia , Amido/metabolismo , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Variação Genética , Genótipo , Estresse Oxidativo/genética , Estresse Oxidativo/fisiologia , Plantas Geneticamente Modificadas , Amido/genética
3.
Int J Mol Sci ; 22(11)2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-34073724

RESUMO

Water deficit adversely affects apple (Malus domestica) productivity on the Loess Plateau. Autophagy plays a key role in plant responses to unfavorable environmental conditions. Previously, we demonstrated that a core apple autophagy-related protein, MdATG8i, was responsive to various stresses at the transcript level. Here, we investigated the function of this gene in the response of apple to severe drought and found that its overexpression (OE) significantly enhanced drought tolerance. Under drought conditions, MdATG8iOE apple plants exhibited less drought-related damage and maintained higher photosynthetic capacities compared with the wild type (WT). The accumulation of ROS (reactive oxygen species) was lower in OE plants under drought stress and was accompanied by higher activities of antioxidant enzymes. Besides, OE plants accumulated lower amounts of insoluble or oxidized proteins but greater amounts of amino acids and flavonoid under severe drought stress, probably due to their enhanced autophagic activities. Particularly, MdATG8iOE plants showed higher root hydraulic conductivity than WT plants did under drought conditions, indicating the enhanced ability of water uptake. In summary, the overexpression of MdATG8i alleviated oxidative damage, modulated amino acid metabolism and flavonoid synthesis, and improved root water uptake, ultimately contributing to enhanced drought tolerance in apple.


Assuntos
Família da Proteína 8 Relacionada à Autofagia/metabolismo , Secas , Malus/metabolismo , Estresse Oxidativo , Estresse Fisiológico , Autofagia , Flavonoides/biossíntese , Regulação da Expressão Gênica de Plantas , Malus/genética , Malus/fisiologia , Plantas Geneticamente Modificadas
4.
Hortic Res ; 8(1): 81, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33790273

RESUMO

Water deficit is one of the major limiting factors for apple (Malus domestica) production on the Loess Plateau, a major apple cultivation area in China. The identification of genes related to the regulation of water use efficiency (WUE) is a crucial aspect of crop breeding programs. As a conserved degradation and recycling mechanism in eukaryotes, autophagy has been reported to participate in various stress responses. However, the relationship between autophagy and WUE regulation has not been explored. We have shown that a crucial autophagy protein in apple, MdATG8i, plays a role in improving salt tolerance. Here, we explored its biological function in response to long-term moderate drought stress. The results showed that MdATG8i-overexpressing (MdATG8i-OE) apple plants exhibited higher WUE than wild-type (WT) plants under long-term moderate drought conditions. Plant WUE can be increased by improving photosynthetic efficiency. Osmoregulation plays a critical role in plant stress resistance and adaptation. Under long-term drought conditions, the photosynthetic capacity and accumulation of sugar and amino acids were higher in MdATG8i-OE plants than in WT plants. The increased photosynthetic capacity in the OE plants could be attributed to their ability to maintain optimal stomatal aperture, organized chloroplasts, and strong antioxidant activity. MdATG8i overexpression also promoted autophagic activity, which was likely related to the changes described above. In summary, our results demonstrate that MdATG8i-OE apple lines exhibited higher WUE than WT under long-term moderate drought conditions because they maintained robust photosynthesis, effective osmotic adjustment processes, and strong autophagic activity.

5.
Physiol Plant ; 172(3): 1452-1464, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33432639

RESUMO

Salinity is a major environmental constraint that substantially limits global agricultural productivity. HD-Zip I transcription factors are involved in plant responses to salt stress, but little is known about the HD-Zip I genes in apple (Malus domestica). Here, we characterized the function of an apple HD-Zip I gene (MdHB7-like) and report that its expression is induced by salt stress. To further explore its role in salt stress, we created MdHB7-like overexpressing and RNAi transgenic apple plants. The overexpression of MdHB7-like improved the photosynthetic performance and reduced ROS and Na+ accumulation under salt stress. Plants that overexpressed MdHB7-like also showed increased accumulation of proline and soluble sugars, which may have played an important role in their salt stress tolerance. RNAi suppression of MdHB7-like had the opposite effects. Together, our results demonstrate that MdHB7-like is an important regulator of salt tolerance in apple. Our results provide new insights for future research on the mechanisms by which MdHB7-like promotes salt tolerance and provide a potential target for molecular breeding in apple.


Assuntos
Malus , Regulação da Expressão Gênica de Plantas , Malus/genética , Malus/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Salinidade , Estresse Fisiológico , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
6.
Plant Physiol Biochem ; 147: 77-90, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31846851

RESUMO

Saline-alkali stress is a major abiotic stress limiting plant growth. The selection of saline-alkali-tolerant rootstock is an effective strategy to reduce salinization-alkalization influence in apple production. M. halliana is a highly saline-alkali-resistant apple rootstock in northwestern China. However, few metabolic response studies have been conducted on this species. In plants under saline-alkali stress, the uptake of K, Mg and Zn in M. halliana leaves were inhibited, whereas the absorption of Fe2+, Cu2+ or Mn2+ were increased. Metabolic analysis revealed 140 differentially expressed metabolites, which were mainly involved in alkaloid biosynthesis, phenylalanine biosynthesis, ATP-binding cassette (ABC) transporters, and mineral absorption. Especially, the expression of sucrose, amino acids, alkaloids, flavonoids and carotenoids were significantly upregulated under saline-alkali stress. qRT-PCR analysis demonstrated that NHX8 and ZTP1 involved in Na+ and Fe2+ transport were upregulated, while AKT1, MRS2-4 and ZTP29 involved in K+, Mg2+ and Zn2+ transport were downregulated, respectively. ANT, ATP2A, CALM and SOS2 are involved in Ca2+ signal transduction, and ABCB1, ABCC10 and NatA are key transporters that maintain ionic homeostasis. M. halliana regulates Na+/K+ homeostasis by mediating Ca2+ signalling and ABC transporters. The accumulation of metabolites contributes to improving the saline-alkali resistance of M. halliana because of the scavenging of ROS. An increase in pheophorbide a content in porphyrin and chlorophyll metabolism leads to leaf senescence in M. halliana leaves, which contributes to a reduction in stress-induced injury. These findings provide important insights into the saline-alkali tolerance mechanism in apple, which also provides an important starting point for future research.


Assuntos
Álcalis , Malus , Metaboloma , Tolerância ao Sal , Plântula , China , Malus/genética , Metabolômica , Folhas de Planta/genética , Tolerância ao Sal/genética , Plântula/genética , Estresse Fisiológico/genética
7.
Hortic Res ; 6: 91, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31645949

RESUMO

Saline-alkali stress is a severely adverse abiotic stress limiting plant growth. Malus halliana Koehne is an apple rootstock that is tolerant to saline-alkali stress. To understand the molecular mechanisms underlying the tolerance of M. halliana to saline-alkali stress, an integrated metabolomic and proteomic approach was used to analyze the plant pathways involved in the stress response of the plant and its regulatory mechanisms. A total of 179 differentially expressed proteins (DEPs) and 140 differentially expressed metabolites (DEMs) were identified. We found that two metabolite-related enzymes (PPD and PAO) were associated with senescence and involved in porphyrin and chlorophyll metabolism; six photosynthesis proteins (PSAH2, PSAK, PSBO2, PSBP1, and PSBQ2) were significantly upregulated, especially PSBO2, and could act as regulators of photosystem II (PSII) repair. Sucrose, acting as a signaling molecule, directly mediated the accumulation of D-phenylalanine, tryptophan, and alkaloid (vindoline and ecgonine) and the expression of proteins related to aspartate and glutamate (ASP3, ASN1, NIT4, and GLN1-1). These responses play a central role in maintaining osmotic balance and removing reactive oxygen species (ROS). In addition, sucrose signaling induced flavonoid biosynthesis by activating the expression of CYP75B1 to regulate the homeostasis of ROS and promoted auxin signaling by activating the expression of T31B5_170 to enhance the resistance of M. halliana to saline-alkali stress. The decrease in peroxidase superfamily protein (PER) and ALDH2C4 during lignin synthesis further triggered a plant saline-alkali response. Overall, this study provides an important starting point for improving saline-alkali tolerance in M. halliana via genetic engineering.

8.
Mol Genet Genomics ; 293(6): 1523-1534, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30101382

RESUMO

Iron (Fe) deficiency is a frequent nutritional problem limiting apple production in calcareous soils. The utilization of rootstock that is resistant to Fe deficiency is an effective way to solve this problem. Malus halliana is an Fe deficiency-tolerant rootstock; however, few molecular studies have been conducted on M. halliana. In the present work, a transcriptome analysis was combined with qRT-PCR and sugar measurements to investigate Fe deficiency responses in M. halliana roots at 0 h (T1), 12 h (T2) and 72 h (T3) after Fe deficiency stress. Total of 2473, 661, and 776 differentially expressed genes (DEGs) were identified in the pairs of T2 vs. T1, T3 vs. T1, and T3 vs. T2, respectively. Several DEGs were enriched in the photosynthesis, glycolysis and gluconeogenesis, tyrosine metabolism and fatty acid degradation pathways. The glycolysis and photosynthesis pathways were upregulated under Fe deficiency. In this experiment, sucrose accumulated in Fe-deficient roots and leaves. However, the glucose content significantly decreased in the roots, while the fructose content significantly decreased in the leaves. Additionally, 15 genes related to glycolysis and sugar synthesis and sugar transport were selected to validate the accuracy of the transcriptome data by qRT-PCR. Overall, these results indicated that sugar synthesis and metabolism in the roots were affected by Fe deficiency. Sugar regulation is a way by which M. halliana responds to Fe deficiency stress.


Assuntos
Metabolismo dos Carboidratos/genética , Ferro/deficiência , Malus/genética , Malus/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ferro/metabolismo , Fotossíntese/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Estresse Fisiológico/fisiologia , Açúcares/análise , Açúcares/metabolismo , Transcriptoma/fisiologia
9.
BMC Genomics ; 19(1): 461, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29902966

RESUMO

BACKGROUND: Iron (Fe) is an essential micronutrient for plants. Utilization of Fe deficiency-tolerant rootstock is an effective strategy to prevent Fe deficiency problems in fruit trees production. Malus halliana is an apple rootstock that is resistant to Fe deficiency; however, few molecular studies have been conducted on M. halliana. RESULTS: To evaluate short-term molecular response of M. halliana leaves under Fe deficiency condition, RNA sequencing (RNA-Seq) analyses were conducted at 0 (T1), 0.5 (T2) and 3 d (T3) after Fe-deficiency stress, and the timepoints were determined with a preliminary physiological experiment. In all, 6907, 5328, and 3593 differentially expressed genes (DEGs) were identified in pairs of T2 vs. T1, T3 vs. T1, and T3 vs. T2. Several of the enriched DEGs were related to heme binding, Fe ion binding, thylakoid membranes, photosystem II, photosynthesis-antenna protein, porphyrin and chlorophyll metabolism and carotenoid biosynthesis under Fe deficiency, which suggests that Fe deficiency mainly affects the photosynthesis of M. halliana. Additionally, we found that Fe deficiency induced significant down-regulation in genes involved in photosynthesis at T2 when seedlings were treated with Fe-deficient solution for 0.5 d, indicating that there was a rapid response of M. halliana to Fe deficiency. A strong up-regulation of photosynthesis genes was detected at T3, which suggested that M. halliana was able to recover photosynthesis after prolonged Fe starvation. A similar expression pattern was found in pigment regulation, including genes for coding chlorophyllide a oxygenase (CAO), ß-carotene hydroxylase (ß-OHase), zeaxanthin epoxidase (ZEP) and 9-cis-epoxycarotenoid dioxygenase (NCED). Our results suggest that pigment regulation plays an important role in the Fe deficiency response. In addition, we verified sixteen genes related to photosynthesis-antenna protein, porphyrin and chlorophyll metabolism and carotenoid biosynthesis pathways using quantitative real-time PCR (qRT-PCR) to ensure the accuracy of transcriptome data. Photosynthetic parameters, Chl fluorescence parameters and the activity of Chlase were also determined. CONCLUSIONS: This study broadly characterizes a molecular mechanism in which pigment and photosynthesis-related regulations play indispensable roles in the response of M. halliana to short-term Fe deficiency and provides a basis for future analyses of the key genes involved in the tolerance of Fe deficiency.


Assuntos
Ferro/fisiologia , Malus/genética , Fotossíntese/genética , Transcriptoma , Hidrolases de Éster Carboxílico/metabolismo , Clorofila , Fluorescência , Perfilação da Expressão Gênica , Ferro/química , Malus/enzimologia , Malus/crescimento & desenvolvimento , Malus/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Plântula/enzimologia , Plântula/genética , Plântula/metabolismo , Análise de Sequência de RNA
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...