Transport of Boron by the tassel-less1 Aquaporin Is Critical for Vegetative and Reproductive Development in Maize    . Issue 7 (17th July 2014)

• Record Type: Journal Article
• Authors: Durbak, Amanda R.; Phillips, Kimberly A.; Pike, Sharon; O'Neill, Malcolm A.; Mares, Jonathan; Gallavotti, Andrea; Malcomber, Simon T.; Gassmann, Walter; McSteen, Paula
• Is Part Of: The Plant Cell. Volume 26:Issue 7(2014)
• Page Start: 2978
• Page End: 2995
• Publication Date: 2014-07-17
• DOI: 10.1105/tpc.114.125898
• Languages: English
• ISSNs: 1040-4651

Abstract

Abstract : Identification and analysis of the maize boron (B) transporter mutant tassel-less1 demonstrated that the primary symptoms of B deficiency are defects in vegetative and reproductive meristems, thus providing an explanation for the reductions in yield observed under B-limited conditions. Abstract: The element boron (B) is an essential plant micronutrient, and B deficiency results in significant crop losses worldwide. The maize ( Zea mays ) tassel-less1 ( tls1 ) mutant has defects in vegetative and inflorescence development, comparable to the effects of B deficiency. Positional cloning revealed that tls1 encodes a protein in the aquaporin family co-orthologous to known B channel proteins in other species. Transport assays show that the TLS1 protein facilitates the movement of B and water into Xenopus laevis oocytes. B content is reduced in tls1 mutants, and application of B rescues the mutant phenotype, indicating that the TLS1 protein facilitates the movement of B in planta. B is required to cross-link the pectic polysaccharide rhamnogalacturonan II (RG-II ) in the cell wall, and the percentage of RG-II dimers is reduced in tls1 inflorescences, indicating that the defects may result from altered cell wall properties. Plants heterozygous for both tls1 and rotten ear ( rte ), the proposed B efflux transporter, exhibit a dosage-dependent defect in inflorescence development under B-limited conditions, indicating that both TLS1 and RTE function in the same biological processes. Together, our data provide evidence that TLS1 is a B transport facilitator in maize, highlighting the importance of B homeostasis in meristem function.