College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China.
Int J Mol Sci. 2018 Nov 20;19(11):3673. doi: 10.3390/ijms19113673.
Leaf senescence represents the final stage of leaf development and is regulated by diverse internal and environmental factors. Jasmonates (JAs) have been demonstrated to induce leaf senescence in several species; however, the mechanisms of JA-induced leaf senescence remain largely unknown in tomato plants (). In the present study, we tested the hypothesis that sedoheptulose-1,7-bisphosphatase (SBPase), an enzyme functioning in the photosynthetic carbon fixation in the Calvin⁻Benson cycle, was involved in methyl jasmonate (MeJA)- and dark-induced leaf senescence in tomato plants. We found that MeJA and dark induced senescence in detached tomato leaves and concomitantly downregulated the expression of and reduced SBPase activity. Furthermore, CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9)-mediated mutagenesis of led to senescence-associated characteristics in mutant plants, including loss of chlorophyll, repressed photosynthesis, increased membrane ion leakage, and enhanced transcript abundance of senescence-associated genes. Collectively, our data suggest that repression of SBPase by MeJA and dark treatment plays a role in JA- and dark-induced leaf senescence.
叶片衰老代表了叶片发育的最后阶段，受到多种内部和环境因素的调控。茉莉酸（JAs）已被证明能诱导多种物种的叶片衰老；然而，在番茄植物中，JA 诱导的叶片衰老的机制在很大程度上仍然未知（）。在本研究中，我们检验了这样一个假设，即作为卡尔文-本森循环中光合作用碳固定作用的酶之一的 1,7-二磷酸景天庚酮糖酶（SBPase），参与了甲基茉莉酸（MeJA）和黑暗诱导的番茄叶片衰老。我们发现，MeJA 和黑暗诱导了离体番茄叶片的衰老，并同时下调了 和减少 SBPase 活性的表达。此外，CRISPR/Cas9（成簇规律间隔短回文重复（CRISPR）/CRISPR 相关蛋白 9）介导的 基因的突变导致 突变体植物出现衰老相关特征，包括叶绿素丧失、光合作用受抑制、膜离子泄漏增加和衰老相关基因的转录丰度增加。总的来说，我们的数据表明，MeJA 和黑暗处理对 SBPase 的抑制作用在 JA 和黑暗诱导的叶片衰老中发挥了作用。
