Anthocyanins are a class of products of plant secondary metabolism and are responsible for tubers color in potato. The biosynthesis of anthocyanins is a complex biological process, in which multiple genes are involved including structural genes and regulatory genes. In this study, StAN11, a WD4o-repeat gene, was cloned from potato cultivar Chieftain （Solanum tuberosum L.）. StAN11 （HQ5995o6） contained no intron and its open reading frame （ORF） was 1,o29 bp long, encoding a putative protein of 342 amino acids. In order to verify its role in anthocyanin biosynthesis, StAN11 was inserted behind the CaMV-35S promoter of pCMBIA1304 and the recombination vector was introduced into the potato cultivar Desiree plants by Agrobacterium-mediated transfor- mation. The color of transgenic tuber skin was significantly deepened, compared to the wild-type control, which was highly consistent with the accumulation of anthocyanin and expression of StAN11 in transgenic lines tuber skin. Further analysis on the expression of Flavonone-3-hydroxylase （F3H）,Dihydroflavonol reductase （DFR）, Anthocyanidin synthase （ANS）, and F1avonoid 3-O-glucosyl transferase （3GT） in transgenic plants revealed that only DFR was upregulated. This result suggested that StAN11 regulated anthocyanin biosynthesis in potato by controlling DFR expression and accumulation of anthocyanin could be increased through overexpression of .StAN11 in the tubers with the genetic background of anthocyanin biosynthesis.
Wang LiBing WangMan WangMin ChenJing-Ming YinGhullam Murtaza KaleriRui-Jie ZhangTie-Niu ZuoXiong YouQing Yang
Verticillium wilt of potato is caused by the fungus pathogen Verticillium dahliae. Present sRNA sequencing data revealed that miR482 was in response to V. dahliae infection, but the function in potato is elusive. Here, we characterized potato miR482 family and its putative role resistance to Verticillium wilt. Members of the potato miR482 superfamily are variable in sequence, but all variants target a class of disease-resistance proteins with nucleotide binding site （NBS） and leucine-rich repeat （LRR） motifs. When potato plantlets were infected with V. dahliae, the expression level of miR482e was downregulated, and that of several NBS-LRR targets of miR482e were upregulated. Transgenic potato plantlets overexpressing miR482e showed hypersensitivity to V. dahliae infection. Using sRNA and degradome datasets, we validated that miR482e targets mRNAs of NBS-LRR disease-resistance proteins and triggers the production of trans-acting （ta）- siRNAs, most of which target mRNAs of defense-relatedproteins. Thus, the hypersensitivity of transgenic potato could be explained by enhanced miR482e and miR482e-derived ta- siRNA-mediated silencing on NBS-LRR-disease-resistance pro- teins. It is speculated that a miR482-mediated silencing cascade mechanism is involved in regulating potato resistance against V. dahliae infection and could be a counter defense action of plant in response to pathogen infection.
Liu YangXiaoying MuChao LiuJinghui CaiKe ShiWenjiao ZhuQing Yang
