Transcriptomic and physiological analysis provide new insight into seed shattering mechanism in Pennisetum alopecuroides‘Liqiu’

Abstract Pennisetum alopecuroides is one of the most representative ornamental grass species of Pennisetumgenus. It has unique inflorescence, elegant appearance, and strong stress tolerance. However, the shattering of seeds reduces not only the ornamental effect but also the seed production. In order to understand the potential mechanism of seed shattering in P. alopecuroides, we conducted morphological, histological, physiological, and transcriptomic analyses on P. alopecuroides cv. ‘Liqiu’. According to histological findings, the seed shattering of ‘Liqiu’ is determined by the abscission zone at the base of the pedicel. Correlation analysis showed that seed shattering was significantly correlated with cellulase, lignin, auxin, gibberellin, cytokinin and jasmonic acid. According to histological and physiological findings, accumulation of cellulase and lignin occurs during ‘Liqiu’ seed abscission. We used PacBio full-length transcriptome sequencing (SMRT) combined with next-generation sequencing (NGS) transcriptome technology to improve the transcriptome data of ‘Liqiu’. Transcriptomics further identified many differential genes involved in cellulase, lignin and plant hormone-related pathways. This study will provide new insights into the research on the shattering mechanism of P. alopecuroides.