Shandong Institute of Pomology, Shandong Academy of Agricultural Science, No 66 Longtan Road, Taian 271000, China.
College of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang 453003, China.
Int J Mol Sci. 2019 May 31;20(11):2678. doi: 10.3390/ijms20112678.
The NAC (for NAM, ATAF1,2, and CUC2) proteins family are plant-specific transcription factors, which play important roles in leaf development and response to environmental stresses. In this study, an NAC gene, , isolated from grapevine L. "Yatomi Rose", was shown to be involved in leaf senescence. The quantity of transcripts decreased with advancing leaf senescence in grapevine. Overexpressing the gene in tobacco plants significantly delayed leaf senescence with respect to chlorophyll concentration, potential quantum efficiency of photosystem II (Fv/Fm), and ion leakage. Moreover, exogenous abscisic acid (ABA) markedly reduced the expression of , and the ABA and salicylic acid (SA) concentration was lower in the -overexpressing transgenic plants than in the wild-type plants. The transgenic plants exhibited reduced sensitivity to ABA-induced senescence but no significant change in the sensitivity to jasmonic acid-, SA- or ethylene-induced senescence. Transcriptomic analysis and RNA expression studies also indicated that the transcript abundance of genes associated with ABA biosynthesis and regulation, including 9--epoxycarotenoid dioxygenase (), , zeaxanthin epoxidase1 (), ABA DEFICIENT2 (), , and ABA INSENSITIVE 2 (), was markedly reduced in the -overexpressing plants. These results suggested that plays a role as a negative regulator of leaf senescence by regulating ABA synthesis.
NAC（NAM、ATAF1、2 和 CUC2）蛋白家族是植物特异性转录因子，在叶片发育和对环境胁迫的响应中发挥重要作用。本研究从葡萄藤 L. "Yatomi Rose" 中分离出一个 NAC 基因 ，该基因参与叶片衰老。随着葡萄叶片衰老的进行， 转录本的数量减少。在烟草植物中过表达 基因，相对于叶绿素浓度、光合作用系统 II 的潜在量子效率 (Fv/Fm) 和离子渗漏，明显延迟了叶片衰老。此外，外源脱落酸 (ABA) 显著降低了 的表达，而 -过表达转基因植物中的 ABA 和水杨酸 (SA) 浓度低于野生型植物。与 ABA 诱导衰老相比， 转基因植物表现出降低的敏感性，但对茉莉酸、SA 或乙烯诱导衰老的敏感性没有显著变化。转录组分析和 RNA 表达研究还表明，与 ABA 生物合成和调节相关的基因的转录丰度，包括 9--环氧类胡萝卜素双加氧酶 ()、()、玉米黄质环氧化酶 1 ()、ABA 缺陷 2 ()、()和 ABA 不敏感 2 ()，在 -过表达植物中明显降低。这些结果表明 作为叶片衰老的负调节剂，通过调节 ABA 合成发挥作用。
