Genome-Wide Expression Pattern Analyses of the Arabidopsis Leucine-Rich Repeat Receptor-Like Kinases

Abstract

Receptor-like protein kinases (RLKs) are a large group of transmembrane proteins playing critical roles in cell-cell and cell-environment communications. Based on extracellular domain structures, RLKs were classified into more than 21 subfamilies, among which leucine-rich repeat RLKs (LRR-RLKs) belong to the largest subfamily in plants such as Arabidopsis and rice. In Arabidopsis, there are approximately 223 LRR-RLKs, but only about 60 of which have been functionally described to date. To systematically investigate the roles of LRR-RLKs in regulating plant growth, development, and stress adaptations, we generated promoter::GUS transgenic plants for all 223 LRR-RLK genes in Arabidopsis and analyzed their detailed expression patterns at various developmental stages. The results provide valuable resources for functionally elucidating this large and essential signaling protein subfamily.

RGF1 INSENSITIVE 1 to 5, a group of LRR receptor-like kinases, are essential for the perception of root meristem growth factor 1 in Arabidopsis thaliana

“…We therefore generated two independent series of double, triple, quadruple, and quintuple mutants. Morphological analyses indicated that the defective phenotypes are mainly observed in the root but not significantly in the aerial parts (Supplementary information, Figure S1C-S1E), with quintuple mutant showing the most severe root developmental defects ( Figure 1C and 1D), which is consistent with their expression profiles (Supplementary information, Figure S1A) [32]. Two independent quintuple mutants, rgi1-1 rgi2-1 rgi3-1 rgi4-1 rgi5-1 and rgi1-2 rgi2-2 rgi3-2 rgi4-2 rgi5-2, showed almost identical short root phenotypes, which are only about 20% the length of wild-type plant, Col-0 ( Figure 1C and 1D).…”

“…Second, members of RGIs were found to interact with BAK1 in a yeast two-hybrid analysis (data not shown), which was the primary motivation prompted us to study the functions of the entire clade of RGIs. Third, all BAK1 and its paralogs were found to be expressed in the roots [32]. Finally, most of the characterized ligand-binding npg www.cell-research.com | Cell Research LRR-RLKs use BAK1 and its paralogs as their co-receptors.…”

“…To understand biological roles of these RGIs, we first checked their expression patterns and found that all five genes are expressed in roots, four of which can be detected in the root tips, with the exception of RGI3 (Supplementary information, Figure S1A) [32]. We isolated two independent sets of T-DNA insertion lines for each of these 5 RGIs ( Figure 1B).…”

“…The T-DNA insertion lines, in- , and RGI5 were amplified by PCR and cloned into a pBIB-BASTA-GUS-GWR vector. The obtained transgenic plants were used for GUS staining as described previously [32]. The promoter sequences of SHR, SCR, and WOX5 were amplified by PCR and cloned into a pBIB-BASTA-NLS-YFP-GWR vector and the obtained transgenic plants were used for confocal imaging.…”

“…There are ~223 LRR-RLKs in Arabidopsis [31]. Only about 60 LRR-RLKs have been functionally reported up-to-date [32]. A vast majority of LRR-RLKs still need to be functionally characterized.…”