Reduction of osa-miR171b contributes to rice stripe virus symptoms by regulating its targets, while overexpression attenuates symptoms, providing direct experimental evidence that a plant miRNA affects the development of virus symptoms.

BackgroundSimilar to other eukaryotes, splicing is emerging as an important process affecting development and stress tolerance in plants. Ski-interacting protein (SKIP), a splicing factor, is essential for circadian clock function and abiotic stress tolerance; however, the mechanisms whereby it regulates flowering time are unknown.ResultsIn this study, we found that SKIP is required for the splicing of serrated leaves and early flowering (SEF) pre-messenger RNA (mRNA), which encodes a component of the ATP-dependent SWR1 chromatin remodeling complex (SWR1-C). Defects in the splicing of SEF pre-mRNA reduced H2A.Z enrichment at FLC, MAF4, and MAF5, suppressed the expression of these genes, and produced an early flowering phenotype in skip-1 plants.ConclusionsOur findings indicate that SKIP regulates SWR1-C function via alternative splicing to control the floral transition in Arabidopsis thaliana.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-017-0422-2) contains supplementary material, which is available to authorized users.

Tiller angle is a key factor determining rice plant architecture, planting density, light interception, photosynthetic efficiency, disease resistance, and grain yield. However, the mechanisms underlying tiller angle control are far from clear. In this study, we identified a mutant, termed bta1–1, with an enlarged tiller angle throughout its life cycle. A detailed analysis reveals that BTA1 has multiple functions because tiller angle, shoot gravitropism, and tolerance to drought stress are changed in bta1–1 plants. Moreover, BTA1 is a positive regulator of shoot gravitropism in rice. Shoot responses to gravistimulation are disrupted in bta1-1 under both light and dark conditions. Gene cloning reveals that bta1-1 is a novel mutant allele of LA1 renamed la1-SN. LA1 is able to rescue the tiller angle and shoot gravitropism defects observed in la1-SN. The nuclear localization signal of LA1 is disrupted by la1-SN, causing changes of its subcellular localization. LA1 is required to regulate the expression of auxin transporters and signaling factors that control shoot gravitropism and tiller angle. High-throughput mRNA sequencing is performed to elucidate the molecular and cellular functions of LA1. The results show that LA1 may be involved in the nucleosome and chromatin assembly, and protein-DNA interactions to control gene expression, shoot gravitropism, and tiller angle. Our results provide new insight into the mechanisms whereby LA1 controls shoot gravitropism and tiller angle in rice.