Transcriptome analyses provide insights into the homeostatic regulation of axillary buds in upland cotton (G. hirsutum L.)

Abstract

Background: The axillary bud is an important index of cotton plant-type traits, and the molecular mechanism of axillary bud development in upland cotton has not yet been reported. We obtained a mutant (designated mZ571) with a high-budding phenotype in axillary bud development from the low-budding phenotype variety G. hirsutum Z571 (CCRI 9A02), which provided ideal materials for the study of complex regulatory networks of axillary bud development. In this study, RNA sequencing was carried out to detect gene expression levels during three stages of axillary buds in Z571 (LB, low budding) and mZ571 mutant (HB, high budding). Results: A total of 7162 DEGs were identified in the three groups (HB-E vs. LB-E, HB-G1 vs. LB-G1, HB-G2 vs. LB-G2), including 4014 downregulated and 3184 upregulated DEGs. Additionally, 221 DEGs were commonly identified in all three groups, accounting for approximately 3.09% of the total DEGs. These DEGs were identified, annotated and classified. A significant number of DEGs were related to hormone metabolism, hormone signal transduction, and starch and sucrose metabolism. In addition, 45, 22 and 9 DEGs involved in hormone metabolic pathways and 67, 22 and 19 DEGs involved in hormone signal transduction pathwayspathway were identified in HB-E vs. LB-E, HB-G1 vs. LB-G1, and HB-G2 vs. LB-G2, respectively, suggesting that endogenous hormones are the primary factors influencing cotton axillary bud growth. Hormone and soluble sugar content measurements revealed that mZ571 exhibited higher concentrations of zeatin, gibberellins and soluble sugar in all three stages, which confirmed that these hormone metabolism-, hormone signal transduction-and starch metabolism-related genes showed interaction effects contributing to the divergence of axillary bud growth between mZ571 and Z571. Conclusions: Our results confirmed the importance of endogenous hormones and sugars in the development of axillary buds, and we found that mZ571 plants, with a high-budding phenotype of axillary buds, exhibited higher endogenous hormone and sugar concentrations. Overall, we present a model for the emergence and development of cotton axillary buds that provides insights into the complexity and dynamic nature of the regulatory network during axillary bud emergence and development.

Physiological and Comparative Transcriptome Analyses of the High-Tillering Mutant mtn1 Reveal Regulatory Mechanisms in the Tillering of Centipedegrass (Eremochloa ophiuroides (Munro) Hack.)

“…In this work, the expression level of TPP7 was upregulated in the mtn1 mutant. This result was in agreement with previous studies on Arabidopsis [ 24 ], maize [ 25 ] and upland cotton [ 45 ], which indicated that a high expression level of TPPs could increase the tillering/branch number. The high expression level of the TPP7 gene was consistent with the high soluble sugar concentration and suggested that sugars are an energy source or nutrient aiding in bud growth in high-tillering centipedegrass.…”

“…In addition to plant hormones, sugars are also necessary for tillering, as they can act as an early signal and provide energy during the tillering development process [ 44 , 45 , 46 ]. In this work, the soluble sugar content in the mtn1 mutant was higher than that of the wild-type.…”

Molecular cloning and characterization of GhERF105, a gene contributing to the regulation of gland formation in upland cotton (Gossypium hirsutum L.)

“…Leaves of each lines were collected for library preparation and RNA-sequencing were performed using Illumina HiSeq 2000. DESeq2 program was used to identify differentially expressed genes, (log fold change ≥1 and FDR<0.05) were considered to be the cutoff threshold to determine differentially expressed genes [56][57][58][59]. All sequencing data have been deposited in SRA (www.ncbi.nlm.nih.gov/sra).The accession numbers are SRR12223945, SRR1652393, ERR5006257 and SRR1652403.…”

Molecular cloning and characterization of GhERF105, a gene contributing to the regulation of gland formation in upland cotton (Gossypium hirsutum L.)

“…Programmed cell death (PCD) plays an important role during the development of pigment glands in Gossypium hirsutum leaf tissue [ 42 ]. Ethylene, which regulate the upstream signal molecular during PCD process, mediates the PCD signal by ROS [ 54 ]. Therefore, it is meaningful to investigate the expression pattern of GhERF105 gene in response to stress hormone ethylene stimuli.…”