Project description:WRKY, an important transcription factor family, is widely distributed in the plant kingdom. Many reports focused on analysis of phylogenetic relationship and biological function of WRKY protein at the whole genome level in different plant species. However, little is known about WRKY proteins in the genome of Arachis species and their response to salicylic acid (SA) and jasmonic acid (JA) treatment. In this study, we identified 77 and 75 WRKY proteins from the two wild ancestral diploid genomes of cultivated tetraploid peanut, Arachis duranensis and Arachis ipaënsis, using bioinformatics approaches. Most peanut WRKY coding genes were located on A. duranensis chromosome A6 and A. ipaënsis chromosome B3, while the least number of WRKY genes was found in chromosome 9. The WRKY orthologous gene pairs in A. duranensis and A. ipaënsis chromosomes were highly syntenic. Our analysis indicated that segmental duplication events played a major role in AdWRKY and AiWRKY genes, and strong purifying selection was observed in gene duplication pairs. Furthermore, we translate the knowledge gained from the genome-wide analysis result of wild ancestral peanut to cultivated peanut to reveal that gene activities of specific cultivated peanut WRKY gene were changed due to SA and JA treatment. Peanut WRKY7, 8 and 13 genes were down-regulated, whereas WRKY1 and 12 genes were up-regulated with SA and JA treatment. These results could provide valuable information for peanut improvement.
Project description:WRKY proteins are the zinc finger transcription factors that were first identified in plants. They can specifically interact with the W-box, which can be found in the promoter region of a large number of plant target genes, to regulate the expressions of downstream target genes. They also participate in diverse physiological and growing processes in plants. Prior to this study, a plenty of WRKY genes have been identified and characterized in herbaceous species, but there is no large-scale study of WRKY genes in willow. With the whole genome sequencing of Salix suchowensis, we have the opportunity to conduct the genome-wide research for willow WRKY gene family. In this study, we identified 85 WRKY genes in the willow genome and renamed them from SsWRKY1 to SsWRKY85 on the basis of their specific distributions on chromosomes. Due to their diverse structural features, the 85 willow WRKY genes could be further classified into three main groups (group I-III), with five subgroups (IIa-IIe) in group II. With the multiple sequence alignment and the manual search, we found three variations of the WRKYGQK heptapeptide: WRKYGRK, WKKYGQK and WRKYGKK, and four variations of the normal zinc finger motif, which might execute some new biological functions. In addition, the SsWRKY genes from the same subgroup share the similar exon-intron structures and conserved motif domains. Further studies of SsWRKY genes revealed that segmental duplication events (SDs) played a more prominent role in the expansion of SsWRKY genes. Distinct expression profiles of SsWRKY genes with RNA sequencing data revealed that diverse expression patterns among five tissues, including tender roots, young leaves, vegetative buds, non-lignified stems and barks. With the analyses of WRKY gene family in willow, it is not only beneficial to complete the functional and annotation information of WRKY genes family in woody plants, but also provide important references to investigate the expansion and evolution of this gene family in flowering plants.
Project description:Cucurbita Linn. vegetables have a long history of cultivation and have been cultivated all over the world. With the increasing area of saline-alkali soil, Cucurbita Linn. is affected by salt stress, and calmodulin-binding transcription activator (CAMTA) is known for its important biological functions. Although the CAMTA gene family has been identified in several species, there is no comprehensive analysis on Cucurbita species. In this study, we analyzed the genome of Cucurbita maxima and Cucurbita moschata. Five C. moschata calmodulin-binding transcription activators (CmoCAMTAs) and six C. maxima calmodulin-binding transcription activators (CmaCAMTAs) were identified, and they were divided into three subfamilies (Subfamilies I, II, and III) based on the sequence identity of amino acids. CAMTAs from the same subfamily usually have similar exon-intron distribution and conserved domains (CG-1, TIG, IQ, and Ank_2). Chromosome localization analysis showed that CmoCAMTAs and CmaCAMTAs were unevenly distributed across four and five out of 21 chromosomes, respectively. There were a total of three duplicate gene pairs, and all of which had experienced segmental duplication events. The transcriptional profiles of CmoCAMTAs and CmaCAMTAs in roots, stems, leaves, and fruits showed that these CAMTAs have tissue specificity. Cis-acting elements analysis showed that most of CmoCAMTAs and CmaCAMTAs responded to salt stress. By analyzing the transcriptional profiles of CmoCAMTAs and CmaCAMTAs under salt stress, it was shown that both C. moschata and C. maxima shared similarities against salt tolerance and that it is likely to contribute to the development of these species. Finally, quantitative real-time polymerase chain reaction (qRT-PCR) further demonstrated the key role of CmoCAMTAs and CmaCAMTAs under salt stress. This study provided a theoretical basis for studying the function and mechanism of CAMTAs in Cucurbita Linn.
Project description:Ethylene biosynthesis and signal transduction play critical roles in plant sex differentiation. ACS (1-aminocyclopropane-1-carboxylic acid synthase) is a rate-limiting enzyme in ethylene biosynthesis. However, the understanding of the ACS gene family in Cucurbita maxima is limited. Here, we identified and characterized 13 ACS genes in the C. maxima genome. All ACS genes could be divided into three groups according to a conserved serine residue at the C-terminus. Thirteen CmaACS genes were found to be randomly distributed on 10 of the 20 chromosomes of C. maxima. The ACS gene exhibits different tissue-specific expression patterns in pumpkin, and four ACS genes (CmaACS1, CmaACS4, CmaACS7, and CmaACS9) were expressed specifically in both the female and male flowers of C. maxima. In addition, the expression levels of CmaACS4 and CmaACS7 were upregulated after ethephon and IAA treatments, which ultimately increased the number of female flowers, decreased the position of the first female flower and decreased the number of bisexual flowers per plant. These results provide relevant information for determining the function of the ACS genes in C. maxima, especially for regulating the function of ethylene in sex determination.
Project description:The WRKY family, a large family of transcription factors (TFs) found in higher plants, plays central roles in many aspects of physiological processes and adaption to environment. However, little information is available regarding the WRKY family in cassava (Manihot esculenta). In the present study, 85 WRKY genes were identified from the cassava genome and classified into three groups according to conserved WRKY domains and zinc-finger structure. Conserved motif analysis showed that all of the identified MeWRKYs had the conserved WRKY domain. Gene structure analysis suggested that the number of introns in MeWRKY genes varied from 1 to 5, with the majority of MeWRKY genes containing three exons. Expression profiles of MeWRKY genes in different tissues and in response to drought stress were analyzed using the RNA-seq technique. The results showed that 72 MeWRKY genes had differential expression in their transcript abundance and 78 MeWRKY genes were differentially expressed in response to drought stresses in different accessions, indicating their contribution to plant developmental processes and drought stress resistance in cassava. Finally, the expression of 9 WRKY genes was analyzed by qRT-PCR under osmotic, salt, ABA, H2O2, and cold treatments, indicating that MeWRKYs may be involved in different signaling pathways. Taken together, this systematic analysis identifies some tissue-specific and abiotic stress-responsive candidate MeWRKY genes for further functional assays in planta, and provides a solid foundation for understanding of abiotic stress responses and signal transduction mediated by WRKYs in cassava.
Project description:BackgroundWRKY transcription factors are a superfamily of regulators involved in diverse biological processes and stress responses in plants. However, there is limited knowledge about the WRKY family in camelina (Camelina sativa), an important Brassicaceae oil crop with strong tolerance for various stresses. Here, a genome-wide characterization of WRKY proteins is performed to examine their gene structures, phylogenetics, expression, conserved motif organizations, and functional annotation to identify candidate WRKYs that mediate stress resistance regulation in camelinas.ResultsA total of 242 CsWRKY proteins encoded by 224 gene loci distributed unevenly over the chromosomes were identified, and they were classified into three groups by phylogenetic analysis according to their WRKY domains and zinc finger motifs. The 15 CsWRKY gene loci generated 33 spliced variants. Orthologous WRKY gene pairs were identified, with 173 pairs in the C. sativa and Arabidopsis genomes as well as 282 pairs in the C. sativa and B. napus genomes, respectively. A total of 137 segmental duplication events were observed, but there was no tandem duplication in the camelina genome. Ten major conserved motifs were examined, with WRKYGQK being the most conserved, and several variants were present in many CsWRKYs. Expression analysis revealed that 50% more CsWRKY genes were expressed constitutively, and a set of them displayed tissue-specific expression. Notably, 11 CsWRKY genes exhibited significant expression changes in seedlings under cold, salt, and drought stresses, showing a preferentially inducible expression pattern in response to the stress.ConclusionsThe present article describes a detailed analysis of the CsWRKY gene family and its expression profiles in 12 tissues and under several stress conditions. Segmental duplication is the major force underlying the broad expansion of this gene family, and a strong purifying pressure occurred for CsWRKY proteins during their evolution. CsWRKY proteins play important roles in plant development, with differential functions in different tissues. Exceptionally, eleven CsWRKYs, particularly five alternative spliced isoforms, were found to be the possible key players in mediating plant responses to various stresses. Overall, our results provide a foundation for understanding the roles of CsWRKYs and the precise mechanism through which CsWRKYs regulate high stress resistance as well as the development of stress tolerance cultivars among Cruciferae crops.
Project description:The WRKY family of transcription factors is one of the most important families of plant transcriptional regulators with members regulating multiple biological processes, especially in regulating defense against biotic and abiotic stresses. However, little information is available about WRKYs in pepper (Capsicum annuum L.). The recent release of completely assembled genome sequences of pepper allowed us to perform a genome-wide investigation for pepper WRKY proteins. In the present study, a total of 71 WRKY genes were identified in the pepper genome. According to structural features of their encoded proteins, the pepper WRKY genes (CaWRKY) were classified into three main groups, with the second group further divided into five subgroups. Genome mapping analysis revealed that CaWRKY were enriched on four chromosomes, especially on chromosome 1, and 15.5% of the family members were tandemly duplicated genes. A phylogenetic tree was constructed depending on WRKY domain' sequences derived from pepper and Arabidopsis. The expression of 21 selected CaWRKY genes in response to seven different biotic and abiotic stresses (salt, heat shock, drought, Phytophtora capsici, SA, MeJA, and ABA) was evaluated by quantitative RT-PCR; Some CaWRKYs were highly expressed and up-regulated by stress treatment. Our results will provide a platform for functional identification and molecular breeding studies of WRKY genes in pepper.
Project description:WRKY is one of the largest transcription factor families in plants and plays an important role in plant growth and development as well as in abiotic and biological stresses. However, there is little information about the WRKY family in Melastoma dodecandrum. In this study, 126 WRKY members were identified in M. dodecandrum. According to phylogenetic analysis, they were divided into three major groups, and group II was further divided into five subgroups. MedWRKY genes were unevenly distributed on 12 chromosomes. Additionally, the gene structure and sequence composition were similar within the same group and differed between groups, suggesting their functional diversity. The promoter sequence analysis identified a number of cis-acting elements related to plant growth and development, stress response, and secondary metabolite synthesis in the WRKY gene family. The collinearity analysis showed that gene replication events were the main driving force of MedWRKY gene evolution. The transcriptome data and RT-qPCR analysis suggested that MedWRKY genes had higher expression in the roots and ripe fruit of M. dodecandrum. In short, this paper lays a foundation for further study of the functions and molecular mechanism of M. dodecandrum WRKY gene family.
Project description:WRKY transcription factors play pivotal roles in regulation of stress responses. This study identified 79 WRKY genes in potato (Solanum tuberosum). Based on multiple sequence alignment and phylogenetic relationships, WRKY genes were classified into three major groups. The majority of WRKY genes belonged to Group II (52 StWRKYs), Group III had 14 and Group I consisted of 13. The phylogenetic tree further classified Group II into five sub-groups. All StWRKY genes except StWRKY79 were mapped on potato chromosomes, with eight tandem duplication gene pairs and seven segmental duplication gene pairs found from StWRKY family genes. The expression analysis of 22 StWRKYs showed their differential expression levels under various stress conditions. Cis-element prediction showed that a large number of elements related to drought, heat and salicylic acid were present in the promotor regions of StWRKY genes. The expression analysis indicated that seven StWRKYs seemed to respond to stress (heat, drought and salinity) and salicylic acid treatment. These genes are candidates for abiotic stress signaling for further research.