Light filtering by epidermal flavonoids during the resistant response of cotton to Xanthomonas protects leaf tissue from light-dependent phytoalexin toxicity

Ultraviolet-absorbing pigments accumulate in red epidermal cells surrounding and sometimes over infection sites. The two principal ones have been identified as cyanidin-3-O-β-glucoside (1) and quercetin-3-O-β-glucoside (2).