Dissecting the distyly response to pollination using metabolite profiling in heteromorphic incompatibility system interactions of Plumbago auriculata Lam

Abstract

Heteromorphic self-incompatibility (HetSI) is a strategy used to prevent selfing while favouring outcrossing in angiosperm. Although the genome, proteome and metabolome of homomorphic self-incompatibility (HomSI) have been investigated, metabolome findings have shown that energy deficiency is one of the factors leading to HomSI. However, the mechanism of HetSI remains unclear. This study investigates the alterations of metabolite fluxes in HetSI. Here, metabolic changes present in dimorphic styles as well as between self-incompatibility (SI) and self-compatibility (SC) pollinations of Plumbago auriculata Lam were simultaneously determined by gas chromatography–mass spectrometry (GC–MS). Fifty-three metabolites, mainly including other organic acids, amino acids, carbohydrates/glycosides, fatty acids/lipids, amines, amides, flavonoids and alcohols, were detected. The overall results showed that carbohydrates, which may affect pollen germination and pollen tube growth rate on stigmas, were abundant in S (short styles without pollination). Moreover, energy deficiency may not be a reason for HetSI because we found inflated levels of metabolites in SI pollinations. This study provided detailed insight into metabolic changes in HetSI and evidence for further studies of HetSI.