GmLCLs negatively regulate ABA perception and signalling genes in soybean leaf dehydration response

Abstract

The circadian clock allows plants to actively adapt to daily environmental changes through temporal regulation of physiological traits. In response to drought stress, circadian oscillators gate ABA signalling, but the molecular mechanisms remain unknown, especially in crops. Here, we investigated the role of soybean circadian oscillators GmLCLa1, GmLCLa2, GmLCLb1 and GmLCLb2 in leaf water stress response. Under dehydration stress, the GmLCL quadruple mutant had decreased leaf water loss. We found that the dehydration treatment delayed the peak expression of GmLCL genes by 4 hr. In addition, the circadian clock in hairy roots also responded to ABA, which led to a free‐running rhythm with shortened period. Importantly, in the gmlclq quadruple mutant, diurnal expression phases of several circadian‐regulated ABA receptor, ABA catabolism and ABA signalling‐related genes were shifted significantly to daytime. Moreover, in the gmlclq mutant leaf, expression of GmPYL17, GmCYP707A, GmABI2 and GmSnRK2s was increased under water dehydration stress. In summary, our results show that GmLCLs act as negative regulators of ABA signalling in leaves during dehydration response.

Towards Developing Drought-smart Soybeans

“…CRISPR/cas9 has been successfully employed to characterise soybean drought-responsive genes using knock-down approaches. For example, CRISPR/cas9mediated mutagenesis of soybean circadian rhythm genes (GmLCLs) generated mutant plants with decreased water loss under dehydration stress conditions (Yuan et al, 2021). Interestingly, breeding and genetic transformation methods have successfully delivered improved soybeans that have been tested in laboratory, glasshouse or field conditions and a few of these varieties have also been approved for commercial production.…”

Time‐series transcriptomics reveals a drought‐responsive temporal network and crosstalk between drought stress and the circadian clock in foxtail millet

“…Furthermore, the phase of circadian genes moved to 12 h at DN 16, 20, and 24, and the amplitude significantly changed (Figure S7b,c). It was recently reported that the phase of the circadian oscillator LHY‐CCA1‐LIKE ortholog ( GmLCL ) gene was delayed under drought stress in soybeans [ Glycine max (L.)] (Yuan et al., 2021), which implied that drought stress perturbed the circadian clock and movement of the phase may be a strategy for enabling plant adaptation to drought stress during a specific time.…”

Soybean GmMYB133 Inhibits Hypocotyl Elongation and Confers Salt Tolerance in Arabidopsis

“…Several studies showed that CCA1 -like MYB s play important roles in response to diverse stresses ( Lai et al, 2012 ; Li et al, 2019a ; Chen S. et al, 2020 ; Yuan et al, 2021 ). To investigate if GmMYB133 is involved in response to abiotic stresses, its expression pattern was determined under cold, drought, and salt stresses.…”

“…Previously, we identified 54 soybean CCA1 -like genes by data mining against the soybean genome database ( Bian et al, 2017a ). However, only few soybean CCA1 -like genes have been functionally studied such as GmLHY s, GmLCL s, GmMYB138a , GmMYB176 , and GmMYB177 , which are associated with the regulation of plant height and internode, isoflavonoid accumulation, ABA perception, and signaling pathway, or in response to stresses ( Liao et al, 2008 ; Li et al, 2012 ; Bian et al, 2017a ; Wang et al, 2021 ; Yuan et al, 2021 ). Recently, GmMYB133 was reported to be involved in the regulation of isoflavonoid accumulation ( Bian et al, 2018 ).…”