Characterization of the Gh4CL gene family reveals a role of Gh4CL7 in drought tolerance
Characterization of the Gh4CL gene family reveals a role of Gh4CL7 in drought tolerance
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DOI：
10.1186/s12870-020-2329-2
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发表时间：
2020-03-23
影响因子：
5.3
通讯作者：
Li, Yan-Jun
中科院分区：
文献类型：
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作者：
Sun, Shi-Chao;Xiong, Xian-Peng;Li, Yan-Jun
背景植物4-香豆酸-CoA连接酶（4-coumartate-CoA ligases，4CL）在非生物胁迫下的功能已被研究，但棉花（G. hirsutum L.）以及它们在应对干旱胁迫中的作用。结果在全基因组范围内鉴定了G.以陆地棉为材料，研究了4CL基因在棉花不同组织中的表达谱以及在胁迫条件下的表达谱，旨在鉴定与耐旱性相关的4CL基因。我们在G.多毛类植物聚为三类。同一类别的基因通常具有相似的基因结构和基序组成。在Gh4 CL基因的启动子中发现了许多与胁迫和激素反应相关的顺式元件。在34个Gh4 CL基因中，26个基因至少受到一种非生物胁迫的诱导，10个基因（包括Gh4 CL 7）在聚乙二醇（PEG）模拟干旱胁迫条件下表达上调。利用棉花病毒诱导基因沉默（VIGS）和拟南芥过表达（OE）技术，研究了Gh4 CL 7在棉花耐旱性中的生物学功能。GH4 CL 7基因沉默棉花对干旱胁迫表现出更强的敏感性，这可能是由于相对含水量（RWC）、叶绿素含量和抗氧化酶活性降低，气孔开度增大，丙二醛（MDA）和过氧化氢（H2 O2）含量增加所致。然而，过量表达Gh4 CL 7的拟南芥品系对干旱胁迫的耐受性更强，这与干旱胁迫条件下抗氧化酶活性的提高、MDA和H2 O2积累的减少以及胁迫相关基因的上调有关。此外，与它们各自的对照相比，Gh4 CL 7沉默的棉花植物和Gh4 CL 7过表达的拟南芥品系的木质素含量分别减少了20%和增加了10%。与木质素生物合成相关的基因PAL、CCoAOMT、COMT、CCR和CAD在Gh4 CL 7基因沉默植株中的表达量均低于对照。这些结果表明，Gh4 CL 7基因对干旱胁迫有积极的响应，有可能成为棉花抗旱性改良的候选基因。结论对高地棉4CL基因家族进行了鉴定，揭示了Gh4 CL 7在陆地棉木质素合成和耐旱性中的作用。
Background The function of 4-coumarate-CoA ligases (4CL) under abiotic stresses has been studied in plants, however, limited is known about the 4CL genes in cotton (G. hirsutum L.) and their roles in response to drought stress. Results We performed genome-wide identification of the 4CL genes in G. hirsutum and investigated the expression profiles of the identified genes in various cotton tissues and in response to stress conditions with an aim to identify 4CL gene(s) associated with drought tolerance. We identified 34 putative 4CL genes in G. hirsutum that were clustered into three classes. Genes of the same class usually share a similar gene structure and motif composition. Many cis-elements related to stress and phytohormone responses were found in the promoters of the Gh4CL genes. Of the 34 Gh4CL genes, 26 were induced by at least one abiotic stress and 10 (including Gh4CL7) were up-regulated under the polyethylene glycol (PEG) simulated drought stress conditions. Virus-induced gene silencing (VIGS) in cotton and overexpression (OE) in Arabidopsis thaliana were applied to investigate the biological function of Gh4CL7 in drought tolerance. The Gh4CL7-silencing cotton plants showed more sensitive to drought stress, probably due to decreased relative water content (RWC), chlorophyll content and antioxidative enzyme activity, increased stomatal aperture, and the contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2). Arabidopsis lines overexpressing Gh4CL7, however, were more tolerant to drought treatment, which was associated with improved antioxidative enzyme activity, reduced accumulation of MDA and H2O2 and up-regulated stress-related genes under the drought stress conditions. In addition, compared to their respective controls, the Gh4CL7-silencing cotton plants and the Gh4CL7-overexpressing Arabidopsis lines had a similar to 20% reduction and a similar to 10% increase in lignin content, respectively. The expression levels of genes related to lignin biosynthesis, including PAL, CCoAOMT, COMT, CCR and CAD, were lower in Gh4CL7-silencing plants than in controls. Taken together, these results demonstrated that Gh4CL7 could positively respond to drought stress and therefore might be a candidate gene for improvement of drought tolerance in cotton. Conclusion We characterized the 4CL gene family in upland cotton and revealed a role of Gh4CL7 in lignin biosynthesis and drought tolerance.