A family of auxin conjugate hydrolases from Solanum lycopersicum and analysis of their roles in flower pedicel abscission
A family of auxin conjugate hydrolases from Solanum lycopersicum and analysis of their roles in flower pedicel abscission
复制标题
番茄生长素结合水解酶家族及其在花蒂脱落中的作用分析
DOI：
10.1186/s12870-019-1840-9
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发表时间：
2019-06-03
影响因子：
5.3
通讯作者：
Li, Tianlai
中科院分区：
文献类型：
--
作者：
Fu, Xin;Shi, Zihang;Li, Tianlai
背景：生长素结合物被水解以释放游离的生长素，以确保组织内确定的细胞生长素水平或梯度，以实现正确的发育或对环境信号的响应。脱落区（AZ）中的生长素浓度被认为在介导脱落滞后期中发挥重要作用。 结果：在本研究中，7个番茄ILR1样SlILL基因的完整cDNA序列被鉴定和表征，所有SlILL都被发现具有生长素缀合物水解活性。不同生长素结合物对脱落的影响将IAA-Ile确定为候选物，以确定生长素结合物和生长素结合物在脱落中的水解功能。用IAA-Ile处理不同时间的花梗外植体表明，6 h前施用可有效延缓脱落。 IAA-Ile预孵育2小时足以抑制脱落。结果表明，AZ内没有足够的生长素结合物来抑制脱落，应用外源生长素结合物抑制脱落的最佳时间是6 h前。用放线菌酮（CHX，一种蛋白质生物合成抑制剂）治疗表明，生长素结合物水解酶的从头合成也是延迟脱落所必需的。在脱落过程中，SlILL1、5和6显示出脱落相关基因的表达模式，而SlILL1、3、5、6和7则显示出表达增加的趋势，这些共同可能有助于延迟脱落。利用病毒诱导的基因沉默技术沉默SlILL1、3、5、6和7的表达，结果表明SlILL1、5和6是番茄脱落的主要介导者。结论：在脱落过程中，生长素的抑制呈浓度依赖性，AZ中生长素的浓度受水解的生长素结合物的调节。 SlILR1、5和6在花蒂脱落中起关键作用。
Background:Auxin conjugates are hydrolyzed to release free auxin to ensure defined cellular auxin levels or gradients within tissues for proper development or response to environmental signals. The auxin concentration in the abscission zone (AZ) is thought to play an important role in mediating the abscission lag phase.Results:In this study, the full cDNA sequences of seven tomato ILR1-like SlILL genes were identified and characterized, All SlILLs were found to have auxin conjugate hydrolysis activity. The effects of different auxin conjugates on abscission identified IAA-Ile as a candidate to determine the auxin conjugate and auxin conjugate hydrolysis functions in abscission. Treatment of pedicel explants with IAA-Ile for different times showed that application before 6 h could effectively delay abscission. IAA-Ile pre-incubation for 2 h was sufficient to inhibit abscission. These results showed that there is not sufficient auxin conjugates in the AZ to inhibit abscission, and the optimal time to inhibit abscission by the application of exogenous auxin conjugates is before 6 h. Treatment with cycloheximide (CHX, a protein biosynthesis inhibitor) indicated that de novo synthesis of auxin conjugate hydrolases is also required to delay abscission. During abscission, SlILL1, 5, and 6 showed abscission-related gene expression patterns, and SlILL1, 3, 5, 6, and 7 showed increasing expression trends, which collectively might contribute to delay abscission. Silencing the expression of SlILL1, 3, 5, 6, and 7 using virus-induced gene silencing showed that SlILL1, 5, and 6 are major mediators of abscission in tomato.Conclusions:In the process of abscission, auxin inhibition is concentration dependent, and the concentration of auxin in the AZ was regulated by hydrolyzed auxin conjugates. SlILR1, 5, and 6 play a key role in flower pedicel abscission.