Alos E, Martinez-Fuentes A, Reig C, Mesejo C, Rodrigo M J, Agustí M, Zacarías L
Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Av. Agustín Escardino 7, 46980 Paterna, Valencia, Spain.
Instituto Agroforestal Mediterráneo, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.
J Plant Physiol. 2017 Mar;210:64-71. doi: 10.1016/j.jplph.2016.12.008. Epub 2016 Dec 19.
In order to gain insights into the controversial ripening behavior of loquat fruits, in the present study we have analyzed the expression of three genes related to ethylene biosynthesis (ACS1, ACO1 and ACO2), two ethylene receptors (ERS1a and ERS1b), one signal transduction component (CTR1) and one transcription factor (EIL1) in peel and pulp of loquat fruit during natural ripening and also in fruits treated with ethylene (10μLL) and 1-MCP (10μLL), an ethylene action inhibitor. In fruits attached to or detached from the tree, a slight increase in ethylene production was detected at the yellow stage, but the respiration rate declined progressively during ripening. Accumulation of transcripts of ethylene biosynthetic genes did not correlate with changes in ethylene production, since the maximum accumulation of ACS1 and ACO1 mRNA was detected in fully coloured fruits. Expression of ethylene receptor and signaling genes followed a different pattern in peel and pulp tissues. After fruit detachment and incubation at 20°C for up to 6days, ACS1 mRNA slightly increased, ACO1 experienced a substantial increment and ACO2 declined. In the peel, these changes were advanced by exogenous ethylene and partially inhibited by 1-MCP. In the pulp, 1-MCP repressed most of the changes in the expression of biosynthetic genes, while ethylene had almost no effects. Expression of ethylene perception and signaling genes was barely affected by ethylene or 1-MCP. Collectively, a differential transcriptional regulation of ethylene biosynthetic genes operates in peel and pulp, and support the notion of non-climacteric ripening in loquat fruits. Ethylene action, however, appears to be required to sustain or maintain the expression of specific genes.
为了深入了解枇杷果实具有争议性的成熟行为，在本研究中，我们分析了与乙烯生物合成相关的三个基因（ACS1、ACO1和ACO2）、两个乙烯受体（ERS1a和ERS1b）、一个信号转导组分（CTR1）和一个转录因子（EIL1）在枇杷果实自然成熟过程中以及在乙烯（10μLL）和乙烯作用抑制剂1-MCP（10μLL）处理的果实的果皮和果肉中的表达情况。在树上附着或采下的果实中，在黄色阶段检测到乙烯产量略有增加，但呼吸速率在成熟过程中逐渐下降。乙烯生物合成基因转录本的积累与乙烯产量的变化不相关，因为在完全着色的果实中检测到ACS1和ACO1 mRNA的最大积累。乙烯受体和信号基因在果皮和果肉组织中的表达模式不同。果实采下并在20°C下放置长达6天后，ACS1 mRNA略有增加，ACO1大幅增加，而ACO2下降。在果皮中，这些变化被外源乙烯提前，被1-MCP部分抑制。在果肉中，1-MCP抑制了生物合成基因表达的大部分变化，而乙烯几乎没有影响。乙烯感知和信号基因的表达几乎不受乙烯或1-MCP的影响。总体而言，乙烯生物合成基因在果皮和果肉中存在差异转录调控，支持枇杷果实非跃变型成熟的观点。然而，乙烯作用似乎是维持或保持特定基因表达所必需的。
