RESUMEN
Rapid alkalinization factor (RALF) are small secreted peptide hormones that can induce rapid alkalinization in a medium. They act as signaling molecules in plants, playing a critical role in plant development and growth, especially in plant immunity. Although the function of RALF peptides has been comprehensively analyzed, the evolutionary mechanism of RALFs in symbiosis has not been studied. In this study, 41, 24, 17 and 12 RALFs were identified in Arabidopsis, soybean, Lotus and Medicago, respectively. A comparative analysis including the molecular characteristics and conserved motifs suggested that the RALF pre-peptides in soybean represented a higher value of isoelectric point and more conservative motifs/residues composition than other species. All 94 RALFs were divided into two clades according to the phylogenetic analysis. Chromosome distribution and synteny analysis suggested that the expansion of the RALF gene family in Arabidopsis mainly depended on tandem duplication, while segment duplication played a dominant role in legume species. The expression levels of most RALFs in soybean were significantly affected by the treatment of rhizobia. Seven GmRALFs are potentially involved in the release of rhizobia in the cortex cells. Overall, our research provides novel insights into the understanding of the role of the RALF gene family in nodule symbiosis.
Asunto(s)
Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Plantas/metabolismo , Filogenia , Medicago/metabolismo , Glycine max/genética , Glycine max/metabolismo , Verduras/metabolismo , Péptidos/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
Mesocotyl is the crucial organ for pushing buds out of deep water or soil after germination in monocots. Deep direct seeding or mechanized dry seeding cultivation practice requires rice cultivars having long mesocotyl. However, the mechanisms of mesocotyl elongation and domestication remain unknown. Here, our genome-wide association study (GWAS) reveals that natural variations of OsGSK2, a conserved GSK3-like kinase involved in brassinosteroid signaling, determine rice mesocotyl length variation. Variations in the coding region of OsGSK2 alter its kinase activity. It is selected for mesocotyl length variation during domestication. Molecular analyses show that brassinosteroid-promoted mesocotyl elongation functions by suppressing the phosphorylation of an U-type cyclin, CYC U2, by OsGSK2. Importantly, the F-box protein D3, a major positive component in strigolactone signaling, can degrade the OsGSK2-phosphorylated CYC U2 to inhibit mesocotyl elongation. Together, these results suggest that OsGSK2 is selected to regulate mesocotyl length by coordinating strigolactone and brassinosteroid signaling during domestication.
Asunto(s)
Brasinoesteroides/metabolismo , Regulación de la Expresión Génica de las Plantas , Genoma de Planta , Glucógeno Sintasa Quinasa 3/genética , Oryza/genética , Proteínas de Plantas/genética , Tallos de la Planta/genética , Domesticación , Proteínas F-Box/genética , Proteínas F-Box/metabolismo , Germinación/genética , Glucógeno Sintasa Quinasa 3/metabolismo , Lactonas/metabolismo , Oryza/crecimiento & desarrollo , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Tallos de la Planta/anatomía & histología , Tallos de la Planta/crecimiento & desarrollo , Tallos de la Planta/metabolismo , Plantones/genética , Plantones/crecimiento & desarrollo , Plantones/metabolismo , Semillas/genética , Semillas/crecimiento & desarrollo , Semillas/metabolismo , Selección Genética , Transducción de Señal , Uracil-ADN Glicosidasa/genética , Uracil-ADN Glicosidasa/metabolismoRESUMEN
Abscisic acid (ABA) plays an essential role in root hair elongation in plants, but the regulatory mechanism remains to be elucidated. In this study, we found that exogenous ABA can promote rice root hair elongation. Transgenic rice overexpressing SAPK10 (Stress/ABA-activated protein kinase 10) had longer root hairs; rice plants overexpressing OsABIL2 (OsABI-Like 2) had attenuated ABA signaling and shorter root hairs, suggesting that the effect of ABA on root hair elongation depends on the conserved PYR/PP2C/SnRK2 ABA signaling module. Treatment of the DR5-GUS and OsPIN-GUS lines with ABA and an auxin efflux inhibitor showed that ABA-induced root hair elongation depends on polar auxin transport. To examine the transcriptional response to ABA, we divided rice root tips into three regions: short root hair, long root hair and root tip zones; and conducted RNA-seq analysis with or without ABA treatment. Examination of genes involved in auxin transport, biosynthesis and metabolism indicated that ABA promotes auxin biosynthesis and polar auxin transport in the root tip, which may lead to auxin accumulation in the long root hair zone. Our findings shed light on how ABA regulates root hair elongation through crosstalk with auxin biosynthesis and transport to orchestrate plant development.
