CRK28, a cysteine-rich receptor-like kinase, plays a role in root organogenesis and overall growth of plants and antagonizes abscisic acid response in seed germination and primary root growth. Receptor-like kinases (RLK) orchestrate development and adaptation to environmental changes in plants. One of the largest RLK groups comprises cysteine-rich receptor-like kinases (CRKs), for which the function of most members remains unknown. In this report, we show that the loss of function of CRK28 led to the formation of roots that are longer and more branched than the parental (Col-0) plantlets, and this correlates with an enhanced domain of the mitotic reporter CycB1:uidA in primary root meristems, whereas CRK28 overexpressing lines had the opposite phenotype, including slow root growth and reduced lateral root formation. Epidermal cell analyses revealed that crk28 mutants had reduced root hair length and increased trichome number, whereas 35S::CRK28 lines present primary roots with longer root hairs but lesser trichomes in leaves. The overall growth in soil of crk28 mutant and CRK28 overexpressing lines was reduced or enhanced, respectively, when compared to the parental (Col-0) seedlings, while germination, root growth and expression analyses of ABI3 and ABI5 further showed that CRK28 modulates ABA responses, which may be important to fine-tune plant morphogenesis. Our study unravels the participation of RLK signaling in root growth and epidermal cell differentiation.

中文翻译：

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富含半胱氨酸的受体样蛋白激酶 CRK28 调节拟南芥生长发育并影响脱落酸反应

CRK28 是一种富含半胱氨酸的受体样激酶，在植物的根器官发生和整体生长中发挥作用，并在种子萌发和初生根生长中拮抗脱落酸反应。受体样激酶 (RLK) 协调植物的发育和适应环境变化。最大的 RLK 组之一包括富含半胱氨酸的受体样激酶 (CRK)，其中大多数成员的功能仍然未知。在本报告中，我们表明 CRK28 的功能丧失导致形成比亲本 (Col-0) 小植物更长、更分枝的根，这与有丝分裂报告基因 CycB1:uidA 的增强域相关主根分生组织，而 CRK28 过表达系具有相反的表型，包括根生长缓慢和侧根形成减少。表皮细胞分析表明，crk28 突变体的根毛长度减少，毛状体数量增加，而 35S::CRK28 系的初生根具有较长的根毛，但叶中的毛状体较少。与亲本 (Col-0) 幼苗相比， crk28 突变体和 CRK28 过表达系在土壤中的整体生长分别减少或增强，而 ABI3 和 ABI5 的发芽、根生长和表达分析进一步表明 CRK28 调节 ABA 反应，这可能对微调植物形态发生很重要。我们的研究揭示了 RLK 信号在根生长和表皮细胞分化中的作用。与亲本 (Col-0) 幼苗相比， crk28 突变体和 CRK28 过表达系在土壤中的整体生长分别减少或增强，而 ABI3 和 ABI5 的发芽、根生长和表达分析进一步表明 CRK28 调节 ABA 反应，这可能对微调植物形态发生很重要。我们的研究揭示了 RLK 信号在根生长和表皮细胞分化中的作用。与亲本 (Col-0) 幼苗相比， crk28 突变体和 CRK28 过表达系在土壤中的整体生长分别减少或增强，而 ABI3 和 ABI5 的发芽、根生长和表达分析进一步表明 CRK28 调节 ABA 反应，这可能对微调植物形态发生很重要。我们的研究揭示了 RLK 信号在根生长和表皮细胞分化中的作用。