Search

Low temperatures decrease the thidiazuron (TDZ) defoliation efficiency in cotton, while cyclanilide (CYC) combined with TDZ can improve the defoliation efficiency at low temperatures, but the mechanism is unknown. This study analyzed the effect of exogenous TDZ and CYC application on cotton leaf abscissions at low temperatures (daily mean temperature: 15°C) using physiology and transcriptomic analysis. The results showed that compared with the TDZ treatment, TDZ combined with CYC accelerated cotton leaf abscission and increased the defoliation rate at low temperatures. The differentially expressed genes (DEGs) in cotton abscission zones (AZs) were subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses to compare the enriched GO terms and KEGG pathways between the TDZ treatment and TDZ combined with CYC treatment. TDZ combined with CYC could induce more DEGs in cotton leaf AZs at low temperatures, and these DEGs were related to plant hormone and reactive oxygen species (ROS) pathways. CYC is an auxin transport inhibitor. TDZ combined with CYC not only downregulated more auxin response related genes but also upregulated more ethylene and jasmonic acid (JA) response related genes at low temperatures, and it decreased the indole-3-acetic acid (IAA) content and increased the JA and 1-aminocyclopropane-1-carboxylic acid (ACC) contents, which enhanced cotton defoliation. In addition, compared with the TDZ treatment alone, TDZ combined with CYC upregulated the expression of respiratory burst oxidase homologs ( RBOH ) genes and the hydrogen peroxide content in cotton AZs at low temperatures, which accelerated cotton defoliation. These results indicated that CYC enhanced the TDZ defoliation efficiency in cotton by adjusting hormone synthesis and response related pathways (including auxin, ethylene, and JA) and ROS production at low temperatures., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Shu, Sun, Wang, Chen, Yang, Zhang, Han, Li, Liang and Liu.)

Manipulating dietary nutrients, especially protein fractions, holds significance in enhancing the antioxidant capacity and immunity function of ruminants. This study investigated the impact of dietary adjustments in soluble protein (SP) levels, in conjunction with a reduction in crude protein (CP) content, on the antioxidant capacity, inflammatory response, carcass characteristics, and meat quality of sheep. This study had four dietary treatments, including a control diet (CON) adhering to NRC standards with a CP content of 16.7% on a dry matter basis and three diets with an approximately 10% reduction in CP content compared to CON with SP levels (% of CP) of 21.2 (SPA), 25.9 (SPB) and 29.4% (SPC), respectively. Thirty-two healthy male Hu sheep, with an initial live weight of 40.37 ± 1.18 kg and age of 6 months, were randomly divided into four groups to receive these respective diets. Our data revealed no significant differences in slaughter performance among treatments ( p > 0.05), although low-protein treatments decreased the stomachus compositus index ( p < 0.05). Compared with CON, as SP was adjusted to 21.2%, total antioxidant capacity (T-AOC) and catalase (CAT) concentrations were decreased in the serum ( p < 0.05), glutathione peroxidase (GSH-Px) content was decreased in jejunum and ileum ( p < 0.05), superoxide dismutase (SOD) concentration was reduced in the duodenum ( p < 0.05), and malondialdehyde (MDA) content was increased in spleen and ileum ( p < 0.05). On the other hand, pro-inflammatory cytokine (IL-1β, IL-6 and IL-8) contents were upregulated in the serum ( p < 0.05), while immunoglobulin (IgA and IgM) contents were reduced in the duodenum ( p < 0.05) with SP adjustments. Additionally, the SPB and SPC diets reduced the content of saturated fatty acids and increased the content of polyunsaturated fatty acids compared with CON ( p < 0.05), along with retention in the tenderness and water-holding capacity of the longissimus lumborum muscle. In summary, reducing CP by 10% with an SP proportion of ~25-30% improved meat quality without compromising antioxidant capacity and immunity function, while lower SP levels had adverse effects.

Cotton is a major cash crop grown worldwide primarily for fiber and oil seed. As the most important cultural practices for cotton production, single pre-plant irrigation and basal fertilization for cotton plant growth and yield are well documented, but their coupling effects are poorly understood in arid regions. A 2-year outdoor pot trial was conducted to unravel the effects of pre-plant irrigation and basal fertilization on leaf area, root growth, biomass accumulation, and capacity of leaf area and root in cotton plant. Two pre-plant irrigations (i.e., W 80 , well-watered and W 0 , not watered) and two basal dressing fertilizations (F 10 , surface application and F 30 , deep application) were used in the experiments. The aboveground and reproductive biomass were highest in W 80 F 10 after 69 days after emergence. Furthermore, W 80 F 10 increased the root length in the 0-40 cm soil layer and the leaf area and improved the loading boll capacity of the effective root length and leaf area. The effective root length and leaf area had substantial direct effects on the aboveground and root biomass, respectively. Our data suggest that basal fertilizer surface application under adequate pre-plant irrigation is an effective strategy for optimal cotton production, which improves the coordination of water-nutrient absorption and photosynthetic areas and promotes assimilated distribution to the reproductive structures.

Verticillium wilt (VW), caused by infection by Verticillium dahliae, is considered one of the most yield-limiting diseases in cotton. To examine the genetic architecture of cotton VW resistance, we performed a genome-wide association study (GWAS) using a panel of 299 accessions and 85 630 single nucleotide polymorphisms (SNPs) detected using the specific-locus amplified fragment sequencing (SLAF-seq) approach. Trait-SNP association analysis detected a total of 17 significant SNPs at P < 1.17 × 10 -5 (P = 1/85 630, -log 10 P = 4.93); the peaks of SNPs associated with VW resistance on A10 were continuous and common in three environments (RDIG2015, RDIF2015 and RDIF2016). Haplotype block structure analysis predicted 22 candidate genes for VW resistance based on A10&#95;99672586 with a minimum P-value (-log 10 P = 6.21). One of these genes (CG02) was near the significant SNP A10&#95;99672586 (0.26 Mb), located in a 372-kb haplotype block, and its Arabidopsis AT3G25510 homologues contain TIR-NBS-LRR domains that may be involved in disease resistance response. Real-time quantitative PCR and virus-induced gene silencing (VIGS) analysis showed that CG02 was specific to up-regulation in the resistant (R) genotype Zhongzhimian2 (ZZM2) and that silenced plants were more susceptible to V. dahliae. These results indicate that CG02 is likely the candidate gene for resistance against V. dahliae in cotton. The identified locus or gene may serve as a promising target for genetic engineering and selection for improving resistance to VW in cotton., (© 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.)