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The degradation of chloroplast components during postharvest senescence of broccoli florets is delayed by low-intensity visible light pulses
Postharvest Biology and Technology ( IF 7 ) Pub Date : 2020-10-01 , DOI: 10.1016/j.postharvbio.2020.111249
Alejandra Bárcena , José Vera Bahima , Victoria Casajús , Gustavo Martínez , Diana Lauff , Juan José Guiamet , Lorenza Costa

Abstract Senescence in harvested green organs, such as broccoli inflorescences, is a highly regulated process characterized by a massive degradation of chloroplast components. The dismantling of the chloroplast involves small “senescence-associated vacuoles” (SAVs) with high protease activity. The expression of the senescence associated gene, SAG12 (here BoSAG12), which encodes a senescence associated cysteine protease, correlated with SAVs appearance. One environmental factor that delays senescence is low-intensity visible light. Daily irradiation with pulses of 2 h of low-intensity white light (20–25 μmol m−2 s−1) is a promising technology to delay postharvest senescence of broccoli stored at room temperature. The aim of this study was to analyze the effects of low-intensity white (W) and red (R) light treatments on some events related to chloroplast dismantling during postharvest senescence of broccoli inflorescences. We detected that chloroplasts number did not change during postharvest senescence. We found that SAVs participate in the dismantling of chloroplasts during the postharvest senescence of broccoli florets. SAVs appearance occurred earlier than visible yellowing. The two light treatments used, i.e. pulses of low-intensity W and R light, delayed chloroplast changes, including chlorophyll degradation and SAVs appearance. The delay of SAVs appearance was accompanied by the delay of BoSAG12 induction in broccoli florets. Regarding protein degradation, not all proteins analyzed were affected equally. The light treatments had greater effect on the retention of thylakoid proteins than on Rubisco and apparently, the effects of light treatment were higher on proteins from PSII (LHCII) than on those from PSI (LHCI and PsaA).

中文翻译:

低强度可见光脉冲延迟了西兰花小花采后衰老过程中叶绿体成分的降解

摘要 收获的绿色器官(如西兰花花序)的衰老是一个高度受管制的过程,其特征是叶绿体成分的大量降解。叶绿体的分解涉及具有高蛋白酶活性的小“衰老相关液泡”(SAV)。衰老相关基因 SAG12(此处为 BoSAG12)的表达与 SAV 的外观相关,该基因编码衰老相关的半胱氨酸蛋白酶。延迟衰老的环境因素之一是低强度可见光。每天用 2 小时的低强度白光(20-25 μmol m-2 s-1)脉冲照射是一种很有前途的技术,可以延缓室温下储存的西兰花的采后衰老。本研究的目的是分析低强度白光 (W) 和红光 (R) 光处理对西兰花花序采后衰老过程中与叶绿体分解相关的一些事件的影响。我们检测到叶绿体数量在收获后衰老期间没有变化。我们发现 SAV 在西兰花小花的采后衰老过程中参与了叶绿体的分解。SAV 的出现早于可见的泛黄。使用的两种光处理,即低强度的 W 和 R 光脉冲,延迟了叶绿体的变化,包括叶绿素降解和 SAV 的出现。SAV 出现的延迟伴随着西兰花小花中 BoSAG12 诱导的延迟。关于蛋白质降解,并非所有分析的蛋白质都受到同等影响。
更新日期:2020-10-01
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