L2, a chloroplast metalloproteinase, regulates fruit ripening by participating in ethylene autocatalysis under the control of ethylene response factors
L2, a chloroplast metalloproteinase, regulates fruit ripening by participating in ethylene autocatalysis under the control of ethylene response factors
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L2是一种叶绿体金属蛋白酶，在乙烯反应因子的控制下通过参与乙烯自催化来调节果实成熟。
DOI：
10.1093/jxb/erab325
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发表时间：
2021-07-13
影响因子：
6.9
通讯作者：
Zhang, Junhong
中科院分区：
文献类型：
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作者：
Li, Guobin;Wang, Jiafa;Zhang, Junhong
尽管自催化乙烯生物合成在跃变型果实的成熟中起着重要作用，但我们对促进其成熟的网络的了解仍然有限。我们鉴定出了白色果实（wf），这是一种产生白色且成熟缓慢的未成熟果实的番茄突变体。我们发现10号染色体上的倒位破坏了LUTESCENT 2（L2）基因，并且白色果实与lutescent 2等位。使用CRISPR/Cas9技术，我们敲除野生型番茄中的L2，并发现l2-cr突变体产生与白色果实（lutescent 2）非常相似的表型。在l2-cr果实中，叶绿体发育受损，类胡萝卜素和番茄红素的积累比野生型更慢。在果实成熟过程中，l2-cr突变体乙烯释放高峰延迟，乙烯产生量减少，ACO基因的表达受到显著抑制。我们还发现，外源乙烯诱导L2的表达和ERF.B3，乙烯反应因子，结合到L2基因的启动子，并激活其转录。因此，L2的表达受到外源乙烯的调控。这些结果表明，乙烯可能影响L2基因的表达，L2参与番茄果实成熟过程中乙烯的自催化合成。
Although autocatalytic ethylene biosynthesis plays an important role in the ripening of climacteric fruits, our knowledge of the network that promotes it remains limited. We identified white fruit (wf), a tomato mutant that produces immature fruit that are white and that ripen slowly. We found that an inversion on chromosome 10 disrupts the LUTESCENT2 (L2) gene, and that white fruit is allelic to lutescent2. Using CRISPR/Cas9 technology we knocked out L2 in wild type tomato and found that the l2-cr mutants produced phenotypes that were very similar to white fruit (lutescent2). In the l2-cr fruit, chloroplast development was impaired and the accumulation of carotenoids and lycopene occurred more slowly than in wild type. During fruit ripening in l2-cr mutants, the peak of ethylene release was delayed, less ethylene was produced, and the expression of ACO genes was significantly suppressed. We also found that exogenous ethylene induces the expression of L2 and that ERF.B3, an ethylene response factor, binds to the promoter of the L2 gene and activates its transcription. Thus, the expression of L2 is regulated by exogenous ethylene. Taken together, our results indicate that ethylene may affect the expression of L2 gene and that L2 participates in autocatalytic ethylene biosynthesis during tomato fruit ripening.