Genome-wide identification of XTH genes in Liriodendron chinense and functional characterization of LcXTH21

Abstract

Liriodendron chinense is a relic tree species of the family Magnoliaceae with multiple uses in timber production, landscape decoration, and afforestation. L. chinense often experiences drought stress in arid areas. However, the molecular basis underlying the drought response of L. chinense remains unclear. Many studies have reported that the xyloglucan endotransglucosylase/hydrolase (XTH) family plays an important role in drought stress resistance. Hereby, to explore the drought resistance mechanism of L. chinense, we identify XTH genes on a genome-wide scale in L. chinense. A total of 27 XTH genes were identified in L. chinense, and these genes were classified into three subfamilies. Drought treatment and RT-qPCR analysis revealed that six LcXTH genes significantly responded to drought stress, especially LcXTH21. Hence, we cloned the LcXTH21 gene and overexpressed it in tobacco via gene transfer to analyze its function. The roots of transgenic plants were more developed than those of wild-type plants under different polyethylene glycol (PEG) concentration, and further RT-qPCR analysis showed that LcXTH21 highly expressed in root compared to aboveground organs, indicating that LcXTH21 may play a role in drought resistance through promoting root development. The results of this study provide new insights into the roles of LcXTH genes in the drought stress response. Our findings will also aid future studies of the molecular mechanisms by which LcXTH genes contribute to the drought response.

Genome-wide identification and expression analysis of xyloglucan endotransglucosylase/hydrolase genes family in Salicaceae during grafting

“…The length of loop 2 was the key point that determined the XET or XEH activity of XTH proteins. The loop 2 of / , -B and ancestral group is shorter than that of III-A group proteins [34,43] . XET proteins speci cally recognizes xyloglucan and forms new xyloglucan chains to expand call walls [45] .…”

“…Intraspecies collinearity analysis showed the chromosomal distribution of the SpuXTHs and PtrXTHs, which was determined by previous evolutionary events [34] (Figure 1A-B). The SpuXTH32 was distinctively distributed on one chromosome segment due to the incomplete genome assembly.…”

“…They were divided into four groups: / , III-A, III-B and ancestral group. The XET proteins belonging to the / and -B groups have a conserved N-linked glycosylation site, which is thought to be important for protein stability [23,34,41] . Nglycosylation domain was absent almost in all III-A and ancestral group members, which was consistent with our results [42,43] .…”

The DELLA-ABI4-HY5 module integrates light and gibberellin signals to regulate hypocotyl elongation

“…ABI4 mediates the balance of ABA and GA biogenesis by regulating the transcription of ABA and GA metabolic genes in opposite ways during primary seed dormancy and post-germination stages ( Shu et al., 2013 , 2016 , 2018 ). Previously, we reported that ABI4 directly regulates a set of genes involved in hypocotyl elongation, such as EXP2 ( EXPANSIN2 ), XTH5 ( XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE 5 ), and XTH21 , which promote cell wall loosening and cell elongation ( Cho and Kende, 1997 ; Rose et al., 2002 ; Sánchez et al., 2004 ; Shin et al., 2005 ; Miedes et al., 2013 ; Xu et al., 2016 ; Wu et al., 2022 ). However, it remains unclear whether ABI4 is involved in GA signaling for the promotion of hypocotyl elongation.…”