Fig. 7: Evolutionary significance of manipulating extracellular terpenoid metabolism in cotton.

a, b Comparative growth analysis of H. armigera (a) and S. frugiperda (b) larvae fed on leaves from wide type (WT) and GhDP1-knockout (CR-Ghdp1) cotton plants (n = 15 individuals). c, f Disease symptoms of different cotton genotypes upon infection by F. oxysporum (c) or R. solani (f). Scale bar, 5 cm. d, g Index analyses of disease grades on cotton leaves. The proportion of plants exhibiting different levels of disease severity is shown. Disease indexes were assessed for 35 plants inoculated with F. oxysporum (d) and 33 plants inoculated with R. solani (g). e, h Relative fungal biomass in infected plants. For e and h FoActin/GhUBQ7 and Rs18S/GhUBQ7 ratios in WT were set to 1, respectively (n = 6 samples). i Morphological comparison of representative leaves from WT and CR-GhDP1 cotton plants after five days of inoculation with B. cinerea. Scale bars, 1 cm. j, k Quantitative assessment of the lesion area induced by B. cinerea (j) (n = 5 samples) and relative biomass of B. cinerea in the inoculated cotton leaves (k) conducted five days post-inoculation (n = 4 samples). l Biosynthetic pathways of major terpenoid specialized metabolites optimized for cotton defense. In non-green organs, such as late-stage ovules, 1 undergoes oxidative homocoupling at the C7 position mediated by laccases and DPs to form 4, conferring reproductive toxicity to mammals. In green organs such as stems and leaves, 1 selective oxidatized at the C5-position by GhDP1, GhAKR13D2 and oxidants, generating specific radical intermediates that lead to the formation of 2, followed by spontaneous oxidation to produce 3. The substantial accumulation of 3 and its derivatives (5a ~ 5d), along with a minor presence of 4, provides significantly enhanced toxicity towards herbivores and pathogens, compared to 4 alone in green organs. This GhDP1-mediated metabolic redirection underscores cotton’s strategically optimized defensive mechanism. For a, b, e, h, j, k, mean ± s.d., P values were determined by a two-tailed unpaired t-test. Source data are provided as a Source Data file.