Chen Jingxin, Mao Linchun, Mi Hongbo, Lu Wenjing, Ying Tiejin, Luo Zisheng
College of Biosystems Engineering and Food Science, Fuli Institute of Food Science, Zhejiang Key Laboratory of Agro-Food Processing, Zhejiang University, Hangzhou, People's Republic of China.
Plant Cell Rep. 2016 Apr;35(4):733-43. doi: 10.1007/s00299-015-1915-5. Epub 2016 Jan 2.
Three annexin genes may be involved in the ripening progress of strawberry fruit. Phytohormones and calcium regulate the expressions of three annexin genes during strawberry fruit ripening. Plant annexins are multi-functional membrane- and Ca(2+)-binding proteins that are involved in various developmental progresses and stress responses. Three annexins FaAnn5a, FaAnn5b and FaAnn8 cDNA obtained from strawberry fruit encode amino acid sequences of approximately 35 kDa containing four annexin repeats, Ca(2+)-binding site, GTP-binding motif, peroxidase residue, and conserved amino acid residues of tryptophan, arginine and cysteine. During fruit development, the transcript levels of FaAnn5a and FaAnn5b increased while FaAnn5b declined after 3/4R stage. The expression patterns of annexins suggested their potential roles in strawberry fruit development and ripening. Expressions of annexin genes were also highly correlated with hormone levels. In addition, exogenous abscisic acid (ABA) enhanced the expressions of FaAnn5a and FaAnn8 while exogenous auxin (IAA) retarded it. However, both ABA and IAA promoted the transcript levels of FaAnn5b, indicating the independent regulation of annexins in fruit likely due to multi-functions of their large family. The responses of annexin genes to exogenous ABA and IAA inhibitors verified the involvement of annexins in plant hormone signaling. Besides, calcium restrained the expressions of FaAnn5s (FaAnn5a and FaAnn5b) but promoted the expression of FaAnn8. Effects of calcium and ethylene glycol tetraacetic acid (EGTA) on the transcript levels of annexins confirmed that calcium likely mediated hormone signal transduction pathways, which helped to elucidate the mechanism of calcium in fruit ripening. Therefore, FaAnn5s and FaAnn8 might be involved in plant hormones' regulation in the development and ripening of strawberry fruit through calcium signaling in the downstream.
三个膜联蛋白基因可能参与草莓果实的成熟过程。植物激素和钙在草莓果实成熟过程中调节三个膜联蛋白基因的表达。植物膜联蛋白是多功能的膜结合和Ca(2+)结合蛋白，参与各种发育过程和应激反应。从草莓果实中获得的三个膜联蛋白FaAnn5a、FaAnn5b和FaAnn8 cDNA编码约35 kDa的氨基酸序列，包含四个膜联蛋白重复序列、Ca(2+)结合位点、GTP结合基序、过氧化物酶残基以及色氨酸、精氨酸和半胱氨酸的保守氨基酸残基。在果实发育过程中，FaAnn5a和FaAnn5b的转录水平升高，而FaAnn5b在3/4R阶段后下降。膜联蛋白的表达模式表明它们在草莓果实发育和成熟中具有潜在作用。膜联蛋白基因的表达也与激素水平高度相关。此外，外源脱落酸（ABA）增强了FaAnn5a和FaAnn8的表达，而外源生长素（IAA）则抑制了它们的表达。然而，ABA和IAA都促进了FaAnn5b的转录水平，表明膜联蛋白在果实中的独立调节可能是由于其大家族的多功能性。膜联蛋白基因对外源ABA和IAA抑制剂的反应证实了膜联蛋白参与植物激素信号传导。此外，钙抑制了FaAnn5s（FaAnn5a和FaAnn5b）的表达，但促进了FaAnn8的表达。钙和乙二醇四乙酸（EGTA）对膜联蛋白转录水平的影响证实，钙可能介导激素信号转导途径，这有助于阐明钙在果实成熟中的作用机制。因此，FaAnn5s和FaAnn8可能通过下游的钙信号传导参与植物激素对草莓果实发育和成熟的调节。
