RESUMEN
The two-component system (TCS) genes are involved in a wide range of physiological processes in prokaryotes and eukaryotes. In plants, the TCS elements help in a variety of functions, including cell proliferation, response to abiotic and biotic stresses, leaf senescence, nutritional signaling, and division of chloroplasts. Three different kinds of proteins make up the TCS system in plants. These are known as HKs (histidine kinases), HPs (histidine phosphotransfer), and RRs (response regulators). We investigated the genome of Gossypium raimondii and discovered a total of 59 GrTCS candidates, which include 23 members of the HK family, 8 members of the HP family, and 28 members of the RR family. RR candidates are further classified as type-A (6 members), type-B (11 members), type-C (2 members), and pseudo-RRs (9 members). The GrTCS genes were analyzed in comparison with the TCS components of other plant species such as Arabidopsis thaliana, Cicer arietinum, Sorghum bicolor, Glycine max, and Oryza sativa. This analysis revealed both conservation and changes in their structures. We identified 5 pairs of GrTCS syntenic homologs in the G. raimondii genome. All 59 TCS genes in G. raimondii are located on all thirteen chromosomes. The GrTCS promoter regions have several cis-regulatory elements, which function as switches and respond to a wide variety of abiotic stresses. RNA-seq and real-time qPCR analysis showed that the majority of GrTCS genes are differentially regulated in response to salt and cold stress. 3D structures of GrTCS proteins were predicted to reveal the specific function. GrTCSs were docked with abscisic acid to assess their binding interactions. This research establishes the groundwork for future functional studies of TCS elements in G. raimondii, which will further focus on stress resistance and overall development.
RESUMEN
Potassium (K+) is an important macro-nutrient for plants, which comprises almost 10% of plant's dry mass. It plays a crucial role in the growth of plants as well as other important processes related to metabolism and stress tolerance. Plants have a complex and well-organized potassium distribution system (channels and transporters). Cotton is the most important economic crop, which is the primary source of natural fiber. Soil deficiency in K+ can negatively affect yield and fiber quality of cotton. However, potassium transport system in cotton is poorly studied. Current study identified 43 Potassium Transport System (PTS) genes in Gossypium raimondii genome. Based on conserved domains, transmembrane domains, and motif structures, these genes were classified as K+ transporters (2 HKTs, 7 KEAs, and 16 KUP/HAK/KTs) and K+ channels (11 Shakers and 7 TPKs/KCO). The phylogenetic comparison of GrPTS genes from Arabidopsis thaliana, Glycine max, Oryza sativa, Medicago truncatula and Cicer arietinum revealed variations in PTS gene conservation. Evolutionary analysis predicted that most GrPTS genes were segmentally duplicated. Gene structure analysis showed that the intron/exon organization of these genes was conserved in specific-family. Chromosomal localization demonstrated a random distribution of PTS genes across all the thirteen chromosomes except chromosome six. Many stress responsive cis-regulatory elements were predicted in promoter regions of GrPTS genes. The RNA-seq data analysis followed by qRT-PCR validation demonstrated that PTS genes potentially work in groups against environmental factors. Moreover, a transporter gene (GrHAK/KUP/KT8) and two channel genes (GrAKT2.1 and GrAKT1.1) are important candidate genes for plant stress response. These results provide useful information for further functional characterization of PTS genes with the breeding aim of stress-resistant cultivars.