Transgenic expression of flavanone 3‐hydroxylase redirects flavonoid biosynthesis and alleviates anthracnose susceptibility in sorghum

作者：Lanxiang Wang, Andy C. W. Lui, Pui Ying Lam, Guoquan Liu, Ian D. Godwin, Clive Lo · 发表于：Plant Biotechnology Journal · 年份：2020 · DOI：10.1111/pbi.13397 · 被引用次数：67 · 研究领域：Plant Gene Expression Analysis、Photosynthetic Processes and Mechanisms、Plant Molecular Biology Research

Flavonoids are ubiquitous in terrestrial plants with important physiological functions. The in planta flavonoid profile depends on the activities of different biosynthesis enzymes (Figure 1a). Flavanone 3-hydroxylase (F3H) is a key enzyme channelling carbon flow towards the production of 3-hydroxylated flavonoids, including flavonols and anthocyanidins. In Poaceae, F3H-encoding genes are generally inactive in vegetative tissues which accumulate flavone derivatives as the predominant flavonoid metabolites. Meanwhile, sorghum produces 3-deoxyanthocyanidins and flavones as phytoalexins for defence against pathogens such as Colletotrichum sublineola, the causal agent of anthracnose. The occurrences of 3-hydroxylated flavonoids in sorghum are generally not well known. Only in some cultivars, anthocyanin pigments accumulate in mesocotyls of seedlings upon illumination following the activation of F3H and other anthocyanidin biosynthesis genes. Here, we transformed the sorghum inbred line Tx430 with the coding region of SbF3H1 (Sb06g031790) under the control of a maize ubiquitin1 (ubi1) promoter for flavonoid profiling and disease phenotyping. Two independent transformants (OE3 and OE4) were selected for characterizations in T3 generation. SbF3H1 expression was detected in different tissues of the OE lines, but only in spikelets of Tx430 control (Figure 1b). Both OE lines showed no observable phenotypes from seedling to ripening stages. However, seed numbers per head declined by 55.6...