Our previous report indicated that tomato (Solanum lycopersicum) fruit of two contrasting varieties in the chilling tolerance showed the opposite expression pattern of a mitochondrial small heat shock protein (M-sHSP23.8) gene after chilling stress. Thus, the fruit of the relatively tolerant variety Micro-Tom strongly accumulated M-sHSP23.8 transcripts while the susceptible var. Minitomato fruit did not. To test whether M-sHSP23.8 is involved in tomato fruit protection mechanisms against chilling stress, Minitomato fruit overexpressing M-sHSP23.8 (OE23.8) and knockdown Micro-Tom fruit with reduced levels of M-sHSP23.8 (amiR23.8) were developed. After chilling treatment, most of the amiR23.8 fruit failed to ripen normally, showed wilting and skin wrinkles, partial discoloration, and did not reach full red color. On the contrary, these chilling injury symptoms were significantly diminished in OE23.8 fruit, showing less visible deterioration after chilling. Fruit of OE23.8 and amiR23.8 showed opposite patterns of water loss, electrolyte leakage, and expression of the tomato catalase 1 gene compared to control fruit. Membrane lipidome profile evidenced that amiR23.8 fruit showed differential adjustment of extraplastidic and plastidic lipids and variations in the lipid remodeling compared to control fruit, suggesting alterations in the membrane integrity. The high sensitivity of Micro-Tom amiR23.8 fruit and the better performance of Minitomato OE23.8 fruit to chilling treatment indicate that sHSP23.8 may be crucial in the chilling stress tolerance in tomato fruit.

我们以前的报告表明，在低温耐受性下，两个相反品种的番茄（Solanum lycopersicum）果实在逆境胁迫后显示了线粒体小热激蛋白（M-sHSP23.8）基因的相反表达模式。因此，相对耐受品种Micro-Tom的果实强烈积累了M-sHSP23.8转录本，而易感var。Minitomato水果没有。测试是否M-sHSP23.8参与番茄果实的保护机制对抗冷胁迫，樱桃番茄过量表达M-sHSP23.8（OE23.8）和击倒微汤姆水果减少的水平M-sHSP23.8（amiR23。 8）开发。冷藏处理后，大部分amiR23.8果实无法正常成熟，出现萎和皮肤皱纹，部分变色，并且未达到全红色。相反，OE23.8果实中的这些冷害症状明显减轻，冷害后可见的变质程度较小。与对照水果相比，OE23.8和amiR23.8的水果表现出相反的水分流失，电解质渗漏和番茄过氧化氢酶1基因表达模式。膜脂质组分析表明amiR23.8与对照果实相比，该果实显示出质外脂质和质体脂质的差异调节以及脂质重塑的变化，表明膜完整性的改变。Micro-Tom amiR23.8水果的高敏感性和Minitomato OE23.8水果对低温处理的更好性能表明sHSP23.8可能对番茄果实的低温胁迫耐受性至关重要。