雷笋采后木纤化及调控基因差异表达研究

Studies on the Lignification and the Differential Expression of Regulatory Genes in Phyllostachys praecox

为探究雷笋采后贮藏过程中木纤化规律,将雷笋分别置于常温(25℃)和低温(4℃)条件下贮藏,研究木质素含量及组分变化相关酶的活性和基因相对表达量。结果表明:在常温条件贮藏至6 d,笋肉表现出黄化、腐烂等变化。在低温条件下,贮藏至第24天,笋肉出现黄化、腐烂现象。低温贮藏至6 d时,木质素含量为13.22 mg/g,到24 d时木质素含量增至26.31 mg/g。氨基酸总量在低温贮藏条件下变化不大。在常温条件下,其呈缓慢下降趋势,贮藏第6天时氨基酸下降了21.78%。苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、肉桂醇脱氢酶(CAD)和肉桂酸-4-羟化酶(C4H)等木质素代谢相关酶活性随贮藏时间的延长,均呈显著上升趋势。常温贮藏下的酶活性高于低温贮藏的酶活性,表明低温时通过降低雷笋木纤化相关酶活性,减缓木纤化进程。在低温贮藏环境中随着贮藏时间的延长,差异表达下调的基因数不断增加。低温贮藏24d时基因下调程度最明显,上调基因各组差别不大;贮藏12 d时上调基因数最少。LAC-10、POD-10、HCT-10、CAD-10和CCR-10等木质素代谢相关基因相对表达量在低温下整体呈上升趋势,而COMT-10基因相对表达量一直减小。本研究结果为雷笋采后木纤化控制提供了理论参考。

In order to explore the changing of lignin in bamboo shoots,the Phyllostachys praecox were stored at room temperature(25℃)and low temperature(4℃),and the enzyme activity and relative gene expression related to changes in lignin content and components were studied.The results showed that:at room temperature,the bamboo shoots showed changes such as yellowing and decay after stored for 6 days;under low temperature storage conditions,the bamboo shoots showed yellowing and decay until the 24th day.Stored at low temperature for 6 days,the lignin content was 13.22 mg/g,and increased to 26.31 mg/g on the 24th day.The total amount of amino acids did not change much under low-temperature storage conditions,and it showed a slow downward trend at room temperature.On the 6th day,the amino acids decreased by 21.78%at the room-temperature storage.Enzyme activities such as phenylalanine ammonia lyase(PAL),peroxidase(POD),cinnamyl alcohol dehydrogenase(CAD),and cinnamic acid-4-hydroxylase(C4H)showed a significant upward trend with extending storage time.Enzyme activities under room temperature storage were higher than those under low temperature storage.Low temperature reduced the activity of bamboo fiber-related enzymes by inhibiting the expression of genes related to bamboo lignin formation,thereby slowing down the process of lignification.Under the low temperature,the number of genes related to down-regulated expression increased with the extending of storage time.The most significant down-regulation of genes were observed at 24 d,while the amount of up-regulated genes was relatively small,with the smallest number observed at 12 d.The relative expression levels of LAC-10,POD-10,HCT-10,CAD-10,and CCR-10 genes showed an overall upward trend under low temperature storage,while the relative expression level of COMT-10 gene decreased continuously.This study provides a theoretical basis for controlling post-harvest quality of bamboo shoots.