<i>LRR1</i> involved in the abscisic acid signaling pathway to regulate the early growth and development of <i>Arabidopsis thaliana</i>

Phenotypic analyses revealed that <i>lrr1</i> and <i>kin7</i> mutants are less sensitive to the inhibitory effects of ABA on germination and cotyledon greening that is seen in WT. Mutants <i>LRR1</i> and kinase 7 (KIN7) exhibited resistance to ABA and displayed normal growth patterns under control conditions. The double mutant <i>lrr1kin7</i> showed reduced responsiveness to ABA. Conversely, overexpression lines <i>LRR1ox2</i> and <i>LRR1ox10</i> demonstrated heightened sensitivity to ABA, resulting in severe growth reduction. qRT-PCR assay indicated that exogenous application of ABA led to significant down-regulation of <i>ABI3</i>, <i>ABI4</i>, and <i>ABI5</i> transcription factors in <i>LRR1</i> material compared to wild-type WT material. An investigation was conducted to determine the expression pattern and transcriptional level of <i>LRR1</i> in Arabidopsis. The results revealed ubiquitous expression of <i>LRR1</i> across all developmental stages and tissue tested. Subcellular localization assays confirmed the presence of LRR1 on the plasma membrane of cells. Furthermore, BiFC assay, yeast two-hybrid complementation, and GST pull-down assays demonstrated an interaction between LRR1 and PYL6 <i>in vitro</i>. These findings provide substantial insights into the involvement of <i>LRR1</i> in the ABA signaling pathway while regulating seed germination and cotyledon greening during early development in Arabidopsis. This study significantly advances our understanding regarding the correlation between <i>LRR1</i> and ABA signaling pathways with potential applications for enhancing crop stress resistance.