RESUMEN
Biochar has been recognised as an efficacious amendment for the remediation of compound heavy metal contamination in soil. However, the molecular mechanism of biochar-mediated tolerance to compound heavy metal toxicity in cotton is unknown. The objective of this research was to investigate the positive impact of biochar (10â¯g·kg-1) on reducing damage caused by compound heavy metals (Cd, Pb, and As) in cotton (Gossypium hirsutum L.). The results revealed that biochar reduced Cd concentrations by 24.9â¯% (roots), and decreased Pb concentrations by 37.1â¯% (roots) and 59.53â¯% (stems). Biochar maintained ionic homoeostasis by regulating the expression of metal transporter proteins such as ABC, HIPP, NRAMP3, PCR, and ZIP, and genes related to the carbon skeleton and plasma membrane. Biochar also downregulated genes related to photosynthesis, thereby increasing photosynthesis. Biochar re-established redox homoeostasis in cotton by activating signal transduction, which regulated the activity of the enzymes POD, SOD, and CAT activity; and the expression of related genes. This research revealed the molecular mechanism by which biochar confers resistance to the harmful effects of compound heavy metal toxicity in cotton. The application of biochar as a soil amendment to neutralise the toxicity of compound heavy metals is recommended for cash crop production.
RESUMEN
The members of the GRAS gene family play important roles in regulating plant growth and development, but their functions in regulating early plant maturity traits are still unknown. In this study, we used a series of bioinformatics tools to identify GRAS gene family members and investigate the function of the gene family (GhGRAS55) using a genome-wide database of upland cotton samples. A total of 58 members of the GRAS gene family were identified and screened, which were distributed on 21 chromosomes within the whole cotton genome. The results of the phylogenetic analysis showed that the genes of upland cotton, island cotton, African cotton, Raymond cotton, and Arabidopsis were distributed in subfamilies I-VIII, although subfamily II did not contain any upland cotton or Arabidopsis GRAS family members. The structures and other characteristics of the genes in this family were clarified using bioinformatics technology. The transcriptomic sequencing results for early and late maturing cotton species showed that the expression of most GRAS family genes, such as GhGRAS10, GhGRAS5511, and GhGRAS55, was lower in early maturing species than late maturing species. We also found that cotton plants with GhGRAS55 genes that were silenced by virus-induced gene silencing (VIGS) technology showed early bud emergence phenotypes, so it could be speculated that the GhGRAS55 gene has the function of regulating early maturity in cotton.