Involvement of Populus CLEL peptides in root development

Abstract

As one of the major groups of small post-translationally modified peptides, the CLV3/EMBRYO SURROUNDING REGION-RELATED (CLE)-like (CLEL) peptide family has been reported to regulate root growth, lateral root development and plant gravitropic responses in Arabidopsis thaliana. In this study, we identified 12 CLEL genes in Populus trichocarpa and performed a comprehensive bioinformatics analysis on these genes. Among them, five P. trichocarpa CLELs (PtrCLELs) were revised with new gene models. All of these PtrCLEL proteins were structurally similar to the A. thaliana CLELs (AtCLELs), including an N-terminal signal peptide, a conserved C-terminal 13-amino-acid CLEL motif and a variable intermediate region. In silico and quantitative real-time PCR analyses showed that PtrCLELs were widely expressed in various tissues, including roots, leaves, buds and stems. Exogenous application of chemically synthesized PtrCLEL peptides resulted in wavy or curly roots and reduced lateral root formation in A. thaliana. Moreover, germinating Populus deltoides seedlings on a growth medium containing these peptides caused the roots to thicken and to form abnormal lateral roots, in many cases in clusters. Anatomical and histological changes in thickened roots were further investigated by treating Populus 717 cuttings with the PtrCLEL10 peptide. We observed that root thickening was mainly due to an increased number of cells in the epidermis, hypodermis and cortex. The results of our study suggested that PtrCLEL and AtCLEL genes encode proteins with similar protein structures, sequences of peptide motif and peptide activities on developing roots. The activities of PtrCLEL peptides in root development were species-dependent.

Expression Profiling of Flavonoid Biosynthesis Genes and Secondary Metabolites Accumulation in Populus under Drought Stress

“…The 2 −∆∆Ct method was applied to obtain the relative gene expression value [66]. PtActin was used as the reference gene for qRT-PCR [67]. The primers used in this experiment are listed (Supplementary Table S1).…”

Small secreted peptides encoded on the wheat (Triticum aestivum L.) genome and their potential roles in stress responses

“…The BLAST method is often used to predict members of the known SSP families. For example, the poplar CLEL family and the switchgrass CLE family were identified via BLAST ( Tian et al., 2019 ; Tian et al., 2021 ). Another common approach for SSPs prediction is HMMER ( Eddy, 1998 ).…”

A Peptide Encoding Gene MdCLE8 Regulates Lateral Root Development in Apple

“…In our previous study, we identi ed 25 MdCLE genes in apple, and by applying their presumed synthetic peptides (MdCLEp) to Arabidopsis, we found that most of the MdCLEp showed strong effects on root growth and development (Zhang et al). In fact, CLE genes and their synthetic peptides found in other plant species also showed inhibitory effects on plant root growth (Kinoshita et al 2007;Whitford et al 2008;Tian et al 2019), suggesting that CLE peptide plays an important role in the regulation of root system architecture. Here, we found a low-nitrogen induced expression of MdCLE8 gene in apple, which encodes a putative plant peptide and plays an important regulatory role in the growth and development of apple lateral roots.…”