背景:脱落酸(ABA)受体pyrabactin抗性1/PYR1样/ABA受体蛋白的调节成分(PYR/PYL/RCAR)已被证明在ABA信号传导和响应包括干旱在内的各种环境刺激中起关键作用,拟南芥的盐度和渗透胁迫。然而,GhPYL9-5D和GhPYR1-3A是否以及如何,棉花中拟南芥PYL9和PYR1的同源物,对ABA和非生物胁迫的反应功能尚不清楚。
结果:GhPYL9-5D和GhPYR1-3A靶向细胞质和细胞核。GhPYL9-5D和GhPYR1-3A在拟南芥野生型和六元组突变体pyr1pyl1pyl2pyl4pyl5pyl8植物中的过表达导致ABA在种子萌发方面的超敏反应,根生长和气孔关闭,以及幼苗对水分亏缺的耐受性,盐和渗透胁迫。此外,VIGS(病毒诱导的基因沉默)棉花植物,其中GhPYL9-5D或GhPYR1-3A被击倒,显示对聚乙二醇6000(PEG)诱导的干旱的耐受性明显降低,与对照相比,盐度和渗透胁迫。此外,转录组数据显示GhPYL9-5D在根中高表达,GhPYR1-3A在纤维和茎中强烈表达。GhPYL9-5D,用PEG或NaCl处理后,GhPYR1-3A及其同系物在棉花中高表达,这两个基因与氧化还原信号成分共表达,转录因子和生长素信号成分。这些结果表明,GhPYL9-5D和GhPYR1-3A可能通过与激素和其他信号传导成分相互作用在棉花适应盐或渗透胁迫中起重要作用。
结论:GhPYL9-5D和GhPYR1-3A正向调节ABA介导的种子萌发,主根生长和气孔关闭,以及对干旱的耐受性,盐和渗透胁迫可能通过影响拟南芥和棉花中多个下游胁迫相关基因的表达。
BACKGROUND: Abscisic acid (ABA) receptor pyrabactin resistance 1/PYR1-like/regulatory components of ABA receptor proteins (PYR/PYL/RCARs) have been demonstrated to play pivotal roles in ABA signaling and in response to diverse environmental stimuli including drought, salinity and osmotic stress in Arabidopsis. However, whether and how GhPYL9-5D and GhPYR1-3A, the homologues of Arabidopsis PYL9 and PYR1 in cotton, function in responding to ABA and abiotic stresses are still unclear.
RESULTS: GhPYL9-5D and GhPYR1-3A were targeted to the cytoplasm and nucleus. Overexpression of GhPYL9-5D and GhPYR1-3A in Arabidopsis wild type and sextuple mutant pyr1pyl1pyl2pyl4pyl5pyl8 plants resulted in ABA hypersensitivity in terms of seed germination, root growth and stomatal closure, as well as seedling tolerance to water deficit, salt and osmotic stress. Moreover, the VIGS (Virus-induced gene silencing) cotton plants, in which GhPYL9-5D or GhPYR1-3A were knocked down, showed clearly reduced tolerance to polyethylene glycol 6000 (PEG)-induced drought, salinity and osmotic stresses compared with the controls. Additionally, transcriptomic data revealed that GhPYL9-5D was highly expressed in the root, and GhPYR1-3A was strongly expressed in the fiber and stem. GhPYL9-5D, GhPYR1-3A and their homologs in cotton were highly expressed after treatment with PEG or NaCl, and the two genes were co-expressed with redox signaling components, transcription factors and auxin signal components. These results suggest that GhPYL9-5D and GhPYR1-3A may serve important roles through interplaying with hormone and other signaling components in cotton adaptation to salt or osmotic stress.
CONCLUSIONS: GhPYL9-5D and GhPYR1-3A positively regulate ABA-mediated seed germination, primary root growth and stomatal closure, as well as tolerance to drought, salt and osmotic stresses likely through affecting the expression of multiple downstream stress-associated genes in Arabidopsis and cotton.