Abstract
Normal uptake, transportation, and assimilation of primary nutrients are essential to plant growth. Tracheary elements (TEs) are tissues responsible for the transport of water and minerals and characterized by patterned secondary cell wall (SCW) thickening. Exocysts are involved in the regulation of SCW deposition by mediating the targeted transport of materials and enzymes to specific membrane areas. EXO70s are highly duplicated in plants and provide exocysts with functional specificity. In this study, we report the isolation of a rice mutant rapid leaf senescence2 (rls2) that exhibits dwarfism, ferruginous spotted necrotic leaves, decreased hydraulic transport, and disordered primary nutrient assimilation. Histological analysis of rls2-1 mutants has indicated impaired cell expansion, collapsed vascular tissues, and irregular SCW deposition. Map-based cloning has revealed that RLS2 encodes OsEXO70A1, which is one of the 47 members of EXO70s in rice. RLS2 was widely expressed and spatially restricted in vascular bundles. Subcellular localization analysis demonstrated that RLS2 was present on both membrane and nuclear regions. Expression analysis revealed that mutations in rls2 triggers transcriptional fluctuation of orthologous EXO70 genes and affects genes involved in primary nutrient absorption and transport. In brief, our study revealed that RLS2 is required for normal vascular bundle differentiation and primary nutrient assimilation.
Highlights
Primary nutrients, including nitrogen (N), phosphorus (Pi), and potassium ion (K+), are essential for plant growth and are required in larger quantities than other nutrients
By measuring the weight at regular increments, we found that the amount of bleeding sap that was collected from the rls[] mutant plants was much less than that collected from the wild-type (Fig. 2a), indicating that the rls[2] mutation affected the hydraulic transportation efficiency of stems
The results showed that RLS2 mRNA was ubiquitously expressed in most tissues, with highest level in leaves at the booting stage, followed by the spikelets; lower levels were detected in young roots, panicles, and stems (Fig. 5a)
Summary
Primary nutrients, including nitrogen (N), phosphorus (Pi), and potassium ion (K+), are essential for plant growth and are required in larger quantities than other nutrients. Tracheary elements (TEs), which are responsible for the transport of water and minerals in terrestrial plants, are characterized by secondary cell wall (SCW) thickening that present an elaborate pattern[16]. Recent studies have shown that EXO70A1 is primarily expressed in TEs and regulate vesicle trafficking during TE differentiation to mediate patterned secondary cell wall thickening in Arabidopsis thaliana[37]. Primary nutrient transporter or channel gene expression were tissue- regulated in rls[2] mutants, suggesting the possibility that RLS2-mediated vesicle trafficking is responsible for the translocation of integral membrane proteins to specific destinations. The present study has revealed that RLS2 is essential for vascular bundle differentiation and mineral nutrient assimilation, and provides information on the functional complexity of exocysts in rice
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
