Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China.
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China.
Plant Sci. 2022 Aug;321:111322. doi: 10.1016/j.plantsci.2022.111322. Epub 2022 May 16.
Plant phospholipase D (PLD) and its product phosphatidic acid (PA) function in both abiotic and biotic stress signaling. However, to date, a PLD gene conferring the desired resistance to both biotic and abiotic stresses has not been found in cotton. Here, we isolated and identified a PLD gene GhPLDδ from cotton (Gossypium hirsutum), which functions in Verticillium wilt resistance and salt tolerance. GhPLDδ was highly induced by salicylic acid (SA), methyl jasmonate (MeJA), abscisic acid (ABA), hydrogen peroxide, PEG 6000, NaCl, and Verticillium dahliae in cotton plants. The positive role of GhPLDδ in regulating plant resistance to V. dahliae was confirmed by loss- and gain-of-function analyses. Upon chitin treatment, accumulation of PA, hydrogen peroxide, JA, SA, and the expression of genes involved in MAPK cascades, JA- and SA-related defense responses were positively related to the level of GhPLDδ in plants. The treatment by exogenous PA could activate the expression of genes related to MAPK, SA, and JA signaling pathways. Moreover, GhPLDδ overexpression enhanced salt tolerance in Arabidopsis as demonstrated by the increased germination rate, longer seedling root, higher chlorophyll content, larger fresh weight, lower malondialdehyde content, and fully expand rosette leaves. Additionally, the PA content and the expression of the genes of the MAPK cascades regulated by PA were increased in GhPLDδ-overexpressed Arabidopsis under salt stress. Taken together, these findings suggest that GhPLDδ and PA are involved in regulating plant defense against both V. dahliae infection and salt stress.
植物磷脂酶 D（PLD）及其产物磷脂酸（PA）在非生物和生物胁迫信号转导中都有作用。然而，迄今为止，在棉花中尚未发现赋予对生物和非生物胁迫均具有抗性的 PLD 基因。在这里，我们从棉花（Gossypium hirsutum）中分离并鉴定了一个 PLD 基因 GhPLDδ，它在黄萎病抗性和耐盐性中起作用。GhPLDδ在棉花植株中受到水杨酸（SA）、茉莉酸甲酯（MeJA）、脱落酸（ABA）、过氧化氢、PEG 6000、NaCl 和黄萎病菌的高度诱导。通过功能丧失和功能获得分析证实了 GhPLDδ 在调节植物对黄萎病菌抗性中的积极作用。在用几丁质处理后，PA、过氧化氢、JA、SA 的积累以及参与 MAPK 级联反应的基因的表达与植物中 GhPLDδ 的水平呈正相关。外源性 PA 的处理可以激活与 MAPK、SA 和 JA 信号通路相关的基因的表达。此外，GhPLDδ 的过表达增强了拟南芥的耐盐性，表现在发芽率提高、幼苗根较长、叶绿素含量较高、鲜重较大、丙二醛含量较低以及莲座叶完全展开。此外，在盐胁迫下，GhPLDδ 过表达的拟南芥中 PA 含量增加，受 PA 调节的 MAPK 级联反应的基因表达增加。综上所述，这些发现表明 GhPLDδ 和 PA 参与调节植物对黄萎病菌感染和盐胁迫的防御。
