硫化氢抑制的蛋氨酸合酶作为番茄果实成熟的正调控因子。
A Hydrogen-Sulfide-Repressed Methionine Synthase Acts as a Positive Regulator for Fruit Ripening in Tomato.
机构信息
School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China.
Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China.
出版信息
Int J Mol Sci. 2022 Oct 13;23(20):12239. doi: 10.3390/ijms232012239.
Ethylene is a key phytohormone that regulates the ripening of climacteric fruits, and methionine is an indirect precursor of ethylene. However, whether methionine synthase plays a role in fruit ripening in (tomato) is still unknown. In this study, we find that a tomato methionine synthase (named ), which could be repressed at the transcriptional level by hydrogen sulfide (HS), acts as a positive regulator for tomato fruit ripening. By a bioinformatics analysis, it is found that SlMS1 and SlMS2 in tomato are highly homologous to methionine synthases in . The expression pattern of and is analyzed in tomato, and SlMS1 expression is up-regulated during fruit ripening, suggesting its potential role in regulating fruit ripening. A potential bipartite nuclear localization signal is found in the amino acid sequence of SlMS1; thus, SlMS1 is tagged with GFP and observed in the leaves of . Consistently, SlMS1-GFP shows strong nuclear localization and also cytoplasmic localization. The role of in regulating fruit ripening is investigated in tomato fruit by transient silencing (virus-induced gene silencing, VIGS) and transient overexpression. The results show that silencing causes delayed fruit ripening, evidenced by more chlorophyll and less carotenoid accumulation, while overexpression accelerates fruit ripening significantly compared with control. Further investigation shows that overexpression could up-regulate the expression of carotenoid-synthesis-related genes (, , ), chlorophyll-degradation-related genes (, , , ), cell-wall-metabolism-related genes (, , , , ) and ethylene-synthesis-pathway-related genes (, , ), while silencing causes the opposite results. The correlation analysis indicates that expression is negatively correlated with chlorophyll content and positively correlated with carotenoid and ripening-related gene expressions. Taken together, our data suggest that SlMS1 is a positive regulator of tomato fruit ripening and a possible target gene for the ripening-delaying effect of HS.
乙烯是一种调控呼吸跃变型果实成熟的关键植物激素，蛋氨酸是乙烯的间接前体。然而，蛋氨酸合酶是否在番茄果实成熟中发挥作用仍不清楚。在本研究中，我们发现番茄蛋氨酸合酶（命名为 SlMS1）可以被硫化氢（HS）在转录水平上抑制，它作为番茄果实成熟的正调控因子发挥作用。通过生物信息学分析，发现番茄中的 SlMS1 和 SlMS2 与拟南芥中的蛋氨酸合酶高度同源。分析了 和 在番茄中的表达模式，发现 SlMS1 在果实成熟过程中表达上调，表明其在调控果实成熟中可能具有潜在作用。在 SlMS1 的氨基酸序列中发现了一个潜在的二分体核定位信号；因此，将 SlMS1 与 GFP 标记，并在番茄叶片中观察到。同样，SlMS1-GFP 显示出强烈的核定位和细胞质定位。通过瞬时沉默（病毒诱导的基因沉默，VIGS）和瞬时过表达研究了 在调控番茄果实成熟中的作用。结果表明， 沉默导致果实成熟延迟，表现在叶绿素积累增加，类胡萝卜素积累减少，而过表达则显著加速果实成熟。进一步的研究表明， 过表达可以上调类胡萝卜素合成相关基因（ 、 、 ）、叶绿素降解相关基因（ 、 、 、 ）、细胞壁代谢相关基因（ 、 、 、 、 ）和乙烯合成途径相关基因（ 、 、 ）的表达，而过表达则导致相反的结果。相关性分析表明， 表达与叶绿素含量呈负相关，与类胡萝卜素和成熟相关基因表达呈正相关。总之，我们的数据表明 SlMS1 是番茄果实成熟的正调控因子，也是 HS 延迟果实成熟作用的一个可能的靶基因。
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