| As a chimonophilous crop,high temperature is one of the most important abiotic stresses that endanger wheat safety production.Exploring thermotolerance-related genes and analyzing the mechanism of heat stress will provide theoretical guidance for the rapid and efficient cultivation of heat tolerant varieties.High temperature often causes protein damage and a series of physiological and biochemical metabolic process disorders in plants.Timely removal of damaged proteins and nonfunctional proteins has become an important mechanism for plants to resist stress,and the Ubiquitin-proteasome pathway(UPS)plays an important role in the process of protein turnover and elimination of nonfunctional proteins.F-box is one of the largest protein family commonly existing in Eukaryote,and is mainly responsible for the specific recognition of substrates to be degraded as a member of SCF complex.Previous studies have shown that F-box proteins in wheat play active roles in resistance to abiotic stress,but there are few related reports on heat stress.It was determined that the transcripts of wheat F-box gene TaSKIP27 are different before and after treatment by abiotic stress or exogenous hormones in our previous study,and wheat T2 generation seeds with overexpressing TaSKIP27(OE)was obtained.Based on this,Western Blot,RT-qPCR,and physiological and biochemical assays were used to further testify if TaSKIP27 response to abiotic stresses,especially heat stress in wheat.Moreover,bioinformatics software and RTqPCR were used to systematically classify and identify the members of F-box/LRR(FBL)subfamily in wheat,and analyze expression patterns of partial members.Main results are as follows:1.After wheat TcLr15 was treated with three hormones(MeJA,SA,and ABA)and three abiotic stresses(37℃,NaCl,and PEG),Western Blot analysis was used to show the expression of TaSKIP27 at the protein level.Significant upregulation was observed in TcLr15 after treatment by ABA,salt,and heat.2.It was found that the mature period of the OE was slightly later than that of the wild-type(WT)plants,but there was no significant difference in growth rate and yield traits when observing the WT and OE plants in the field in June.Moreover,the OE plants exhibited phenotype of stronger heat resistance than the WT after treatment by high temperature(37℃)during the seedling stage.The expression pattern showed that the TaSKIP27 were significantly increased at 6 hours(h)of heat stress at gene and protein expression levels.In addition,the proline content significantly increased in OE plants after treatment by heat stress for 12 h;The transcript of TaPOD and TaSOD,two genes encoding for antioxidative enzymes,increased at stage of 12 h recovery,and POD activity significantly increased after 12 h of recovery at regular temperature.It was speculated that TaSKIP27 participates in the process of wheat resistance to heat stress by increasing proline content and enhancing POD activity.3.TaSKP1 and TaSLYl are two proteins interacting with TaSKIP27,so we further analyze the expression of these two genes in OE and WT plants in the condition of heat stress.At 6 hours of heat stress,TaSKP1 was transiently upregulated in OE plants,but the expression of TaSLY1 was higher than that of WT control at all time points of heat stress treatment.4.The OE plants was treated with ABA and 300 mmol/L NaCl.The expression of TaSKIP27 protein in OE plants started to increase from 2 h after ABA treatment,and maintained a high expression level until 48 h.After NaCl treatment,the OE plants were more salt-tolerant,and the TaSKIP27 protein level also showed an earlier induced expression than the WT.5.116 TaFBL genes were obtained,which encode 139 TaFBL proteins;TaFBL protein can be divided into five types according to the number of LRR domain and six evolutionary branches;116 TaFBL genes were unevenly distributed on 21 chromosomes of wheat,and segmental duplication was their main way of expansion;FBL subfamily showed different expression patterns in wheat after heat stress. |
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