| Drought is one of the most seriousely natural disasters that cause land desertification and agricultural production reduction.Plants have formed a variety of physiological mechanisms to resist drought in the long-term evolution process,in which it isone of the most effective drought-resistant mechanisms thatwaxes were secretedtoforma tight layer,and also is a main water barrier in plant evolved from aquatic to land.At the same time,the formation of cuticle is also closely related to the plant’s resistance to the invasion of the pests and the organsfusion inplant developing progress.During the formation of the cuticle,the ATP-binding cassette transporter subfamily G11(ABCG11)is responsible for transporting the lipids synthesized by epidermal cells to the epidermal to form the cuticle,but the function is only verified in a few mesophytes whose cuticle is underdeveloped.The function of ABCG11 protein in xerophytesis rarely.Lycium barbarum Bianguo is a variety of Lycium barbarum L,its tender branches and leaves can be used as healthy vegetables and animal feed.The fruit has better nutritional and medicinal value than other varieties of Lycium barbarum L.Meanwhile,Lycium barbarum Bianguo is also a drought-tolerant and salt-tolerant plant with a highly developed cuticle of the epidermis.In this study,the c DNA sequence of the epidermal wax-transport related gene Lb ABCG11 was cloned by reverse transcription PCR(RT-PCR)and RACE form Lycium barbarum Bianguo,and the bioinformatics of the sequence was carried out.Futhermore,the expression levels of Lb ABCG11 in leaves,stems and roots under osmotic stress,salt treatment,ABA and light/dark treatment were detected by real-time fluorescence quantitative PCR(q RT-PCR).The results are as follows:1.Under 80 mmol/L and 160 mmol/L sorbitol osmotic treatment,the average water loss rate of the leaves within 180 min decreased by 11% and 8%,respectively,and the average water loss rate of stems decreased by 10% and 5%,respectively.The average chlorophyll extraction rate in the 150 min inner leaves was reduced by 12%and 8%,respectively.It indicated that under osmotic stress,Lycium barbarum Bianguo can reduce the water loss of the epidermis by reducing the permeability of the shoot epidermis,and improve the water retention capacity to resist water deficit.2.The full length of Lb ABCG11 is 2971 bp,including 2130 bp open reading frame(ORF),555 bp 5’ untranslated region(5’UTR),286 bp 3’ untranslated region(3’UTR),and a 29 bp poly(A)tail,and encoding a 710 amino acids protein,which was predicted to have a molecular weight of 79.39 k D and an isoelectric point of 8.42.The protein has six transmembrane domains and an ABC transporter domain located at the N-terminal,which contains the P-ring of nucleoside triphosphate hydrolase and a15 bpconserved sites of ABC transporter,and a type II ABC transporter domain at the C-terminal.Multiple comparisons of amino acid sequences showed that Lb ABCG11 of Lycium barbarum had 96% and 92% homology with Sl ABCG11 and Cb ABCG11,respectively.3.Lb ABCG11 gene was expressed in leaves,stems and roots of Lycium barbarum L,and osmosis,salt,ABA and light/dark treatment maybe increase the expression leves of Lb ABCG11 gene.Under 80 mmol/L sorbitol osmosis treatment,the transcription abundance of Lb ABCG11 in leaves reached its peak at 36 hours,which was 174% higher than that of the control;,while it reached its peak at 6 hours in stems,which was 47% higher than that of the control;and,it reached its peak at 12 hoursin roots,which was 104% higher than that of the control.The transcriptional abundance of Lb ABCG11 in leaves reached its peak at 12 hours,which was 13%higher than that of the control,reached its peak at 6 hours in stems,which was 120%higher than that of the control,and reached its peak at 3 hours in roots,which was 119%higher than that of the control.50 mmol/L and 100 mmol/L Na Cl induced up-regulation of Lb ABCG11 gene expression in leaves,stems and roots of leaves,but the expression of leaves and stems increased by more than 9 times;roots and stems were induced by 150 mmol/L,200 mmol/L and 300 mmol/L Na Cl.The amount of Lb ABCG11 gene was up-regulated,but the expression of Lb ABCG11 gene in root was down-regulated.Under the treatment of 25 μmol/L,50 μmol/L and 75 μmol/L ABA,the transcript abundance of Lb ABCG11 peaked at 12 h,which increased by 388%,251%and 33%,respectively,and the peak growth rate of stem was 72 h.Although the expression level of leaf and root Lb ABCG11 could be up-regulated by 226% under the treatment of 75 μmol/L ABA for 3h,it was also much lower than that of leaves.The transcript abundance of Lb ABCG11 in the leaves increased by 6 times compared with the control after 96 hours of light irradiation,while the transcript abundance of Lb ABCG11 in roots decreased 20-fold compared to controls.It can be seen that the Lb ABCG11 gene may be involved in the response of plants to abiotic stresses such as osmotic stress and salt stress through the ABA signaling system. |
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