Analysis of expression and interaction proteins of BjuSPL10c in B. juncea

Abstract

• BjuSPL10c was expressed at a high level in flowers and up-regulated at reproductive stage. • Seven potential interactive proteins (BjuB025567, BjuA041065, BjuB033332, BjuA045694, BjuA027365, BjuA031237 and BjuA005619) were screened from B.juncea yeast library of flower buds at squaring stage. • Six (BjuB025567, BjuA041065, BjuB033332, BjuA045694, BjuA031237 and BjuA005619) of those proteins interacted with BjuSPL10c in vivo. • All of these six genes expressing interactive proteins were down-regulated in flowers. Brassica juncea var. tumida Tsen et Lee (Tumorous stem mustard) is a specific vegetable in China. Its tumorous stem can be consumed as fresh vegetable or produced pickle. In practice, early-bolting happens in around 15%, which inhibits B. juncea industry development. SPL is a plant specific transcription factor, plays important roles in flowering and gibberellins (GA) signaling. qRT-PCR assay found that BjuSPL10c was expressed at a high level in flowers and reproductive stage. To explore interactive proteins, BjuSPL10c was used as bait, finally seven proteins were screened and they are BjuB025567, BjuA041065, BjuB033332, BjuA045694, BjuA027365, BjuA031237 and BjuA005619. Further study confirmed that six of those proteins interacted with BjuSPL10c in vivo. qRT-PCR was conducted to understand mRNA expression levels of these six proteins in different tissues and development stages. The results showed that compared with root, mRNAs for all of these six genes were down-regulated in flowers. For different developmental stages, BjuB025567 and BjuA005619 were up-regulated at vegetative stage, down-regulated at reproductive stage; BjuB033332, BjuA045694 and BjuA031237 were significantly up-regulated at both vegetative and reproductive stages; BjuA041065 was showed “down-up-down” expression pattern. Taking all results together, BjuB025567, BjuA041065, BjuB033332, BjuA045694 and BjuA031237 may participate in flowering time regulation through interacting with BjuSPL10c in B. juncea .