AUTHOR=Yang Chaochen , Wu Pengfei , Cao Yongqing , Yang Bingbing , Liu Linxiu , Chen Juanjuan , Zhuo Renying , Yao Xiaohua 

TITLE=Overexpression of dihydroflavonol 4-reductase (CoDFR) boosts flavonoid production involved in the anthracnose resistance

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1038467

DOI=10.3389/fpls.2022.1038467

ISSN=1664-462X

ABSTRACT=<p>The outbreak of anthracnose caused by <italic>Colletotrichum</italic> spp. represents a devastating epidemic that severely affects oil tea (<italic>Camellia oleifera</italic>) production in China. However, the unknown resistance mechanism to anthracnose in <italic>C. oleifera</italic> has impeded the progress of breeding disease-resistant varieties. In this study, we investigated the physiological responses of resistant and susceptible lines during <italic>C. gloeosporioides</italic> infection. Our results showed that the accumulation of malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) in both disease-resistant and susceptible lines increased by <italic>C. gloeosporioides</italic> infection. Also, disease-resistant lines exhibited lower MDA, but higher POD, SOD, and CAT activities compared to susceptible lines. The accumulation of flavonoids in both resistant and susceptible <italic>C. oleifera</italic> leaves increased following <italic>C. gloeosporioides</italic> infection, and the increase was greater in resistant lines. Further, we identified and functionally characterized the dihydroflavonol 4-reductase (<italic>CoDFR</italic>) from the resistant <italic>C. oleifera</italic> line. We showed that the full-length coding sequence (CDS) of <italic>CoDFR</italic> is 1044 bp encoding 347 amino acids. The overexpression of <italic>CoDFR</italic> in tobacco altered the expression of flavonoid biosynthetic genes, resulting in an increased flavonoid content in leaves. <italic>CoDFR</italic> transgenic tobacco plants exhibited increased anthracnose resistance. Furthermore, the transgenic plants had higher salicylic acid content. These findings offer potential insights into the pivotal role of <italic>CoDFR</italic> involved in flavonoid-mediated defense mechanisms during anthracnose invasion in resistant <italic>C. oleifera</italic>.</p>