Correlations between lignin content and related genes, weathering deterioration, and soybean seed quality at pre-harvest

The present study aimed to identify the relationship between lignin content in soybean pods, pod dehiscence rate, gene expression from phenylpropanoid pathway, cell wall lignification, and deterioration of seed due to weather. To evaluate the weathering deterioration, an experiment simulating 150 mm of rainfall was performed in greenhouse conditions. Gene expression was assessed by RT-qPCR. Results showed that soybean cultivars BRS Jiripoca and BRS 388 RR considered tolerant to weathering deterioration, presented higher levels of lignin content in pods. The data showed that dehiscence rate was neither a trait involved in weathering deterioration tolerance nor in lignin content in soybean pods. Lignin content and weathering deterioration were highly negatively correlated, probably due to changes in cell wall permeability to water accordingly to lignin level. Higher expression levels of genes involved in lignin biosynthesis and cell wall lignification were identified in both tolerant cultivars, however, with opposite expression profiles and in different developmental phases, suggesting a possible temporal strategy to cope with environmental adverse conditions.