水杨酸对蛋白核小球藻(Chlorella pyrenoidosa)生长及抗逆相关基因的影响

EFFECTS OF SALICYLIC ACID ON GROWTH AND STRESS-RELATED GENES OF CHLORELLA PYRENOIDOSA

以蛋白核小球藻(Chlorella pyrenoidosa)为研究对象,首先克隆了热激蛋白70(HSP70)和磷酸甘油酸激酶(PGK)基因全长序列,然后研究了0—20μg/m L水杨酸对高温胁迫下HSP70和PGK基因表达,以及蛋白核小球藻生长、可溶性糖和蛋白含量的影响。结果获得了蛋白核小球藻HSP70基因的c DNA序列2405 bp,包括60 bp的5’-非编码区(UTR)、1959 bp的开放阅读框(ORF)和386 bp的3’-UTR和PGK基因的c DNA序列1664 bp,包括35 bp的5’-UTR,1398 bp ORF和231 bp 3’-UTR。序列比较和分析表明该蛋白核小球藻HSP70序列与其它绿藻的同源性高达83%—91%,PGK为70%—75%。荧光定量PCR结果显示随着水杨酸浓度的增加,HSP70和PGK的表达量在12h和24h均有所增加,而在10μg/m L水杨酸浓度下表达量最大,12h时分别为对照组的2.57倍和1.56倍,24h则为1.71倍和1.79倍。1—20μg/m L水杨酸可促进该藻的比生长速率、可溶性糖和蛋白含量的升高。本文结果表明一定浓度水杨酸对高温胁迫蛋白核小球藻有缓解作用,且5和10μg/m L水杨酸的效果最显著。

We cloned heat stock protein 70（HSP70） and phosphoglycerate kinase（PGK） genes, and identified the effects of 0—20.0μg/m L salicylic acid on the gene expression of HSP70 and PGK, algal growth, soluble sugar and protein contents of Chlorella pyrenoidosa under high temperature stress. In this study, we obtained a 2405-bpHSP70 c DNA sequence containing a 60-bp 5＇-untranslated region（UTR）, a 1959-bp open reading frame（ORF）, and a 386-bp 3＇-UTR; and a 1664-bp PGK c DNA sequence containing a 35-bp 5＇-UTR, 1398-bp ORF, and 231-bp 3＇-UTR. Sequence comparison and analysis showed that the homology of HSP70 reached 83%—91% with other green algae, and that of PGK was 70%—75%; both are highly conserved. RT-q PCR showed that with increase in salicylic acid concentration, both expression levels of HSP70 and PGK increased at 12 h and 24 h, maximum in 10μg/m L salicylic acid. Compared to the control, the expression levels of HSP70 and PGK in 10 μg/m L salicylic acid group at 12 h exhibited 2.57-fold and 1.56-fold increase, and 1.71-fold and 1.79-fold at 24 h, respectively. Salicylic acid in 1—20μg/m L concentrations could improve the algal specific growth rate, soluble sugar and protein contents. Therefore, salicylic acid in a certain concentrations could alleviate high temperature stress, and the best results were observed in 5 and 10 μg/m L concentrations.