EMS诱变的‘里格尔87-5’番茄M_2群体突变体表型及其抗坏血酸研究

Phenotype Mutation and Ascorbate Characterization in M_2 Population Derived from EMS Treatment in ‘Ligeer 87-5’ Tomato

构建番茄突变体库对于丰富遗传变异、发掘基因资源具有重要意义。利用1%的甲基磺酸乙酯(EMS)处理‘里格尔87-5’加工番茄种子12 h,对M_2代材料进行农艺学性状与生物学性状鉴定,对部分M_3代材料进行遗传稳定性验证。在M_2代筛出典型突变体,包括早衰、矮化、圆果、低抗坏血酸、黑斑、绿茎、簇生等突变单株。对240个M_2代家系中共1 023个单株全生育期田间表型进行观察鉴定和果实品质测定,共发现90个变异单株,其中13个突变单株同时出现两个或两个以上变异性状,共50个变异性状,总的单株变异频率(突变株/总株数)为8.80%。叶、茎、花、果实和植株发生的变异株数分别为27、7、17、56和21,性状变异频率分别为2.64%、0.68%、1.66%、5.47%和2.05%。其中矮化突变体分子鉴定表明,curl-3基因外显子中C变成T,氨基酸由L变成F,喷施油菜素内酯不能恢复其正常生长,表明curl-3突变导致油菜素内酯信号传导受阻。curl-3突变体叶片与果实中抗坏血酸含量下降,并伴随着叶片中氧化态与还原态抗坏血酸比值增加,这可能与抗坏血酸氧化酶基因AO表达量和AO酶活性增强有关。

Producing mutants by EMS treatment can create novel germplasm for breeding and novel mutants for gene cloning. In this study,seeds of‘Ligeer 87-5＇tomato were treated with 1% ethyl methane sulfonate（EMS）for 12 h. 240 plants were investigated in terms of agronomic and biological traits. Parts of M3 plants were verified for genetic stability. Numerous valuable mutant phenotypes were observed in M2 progeny,including premature aging,dwarf,round fruit,low ascorbic acid content,spots,green stem,cluster growth. Taken together the plant growth and fruit quality in M2 fruits,we found 90 mutant plants with 50 mutant traits in total. The 13 mutant plants had two or more mutant traits simultaneously. The mutation rate of all M2 is 8.80%（mutant lines/total lines）. The mutant number in leaf,stem,floral organ,fruit and plant habit were 27,7,17,56 and 21,respectively. The mutation rates of leaf,stem floral organ,fruit and plant were 2.64%,0.68%,1.66%,5.47% and 2.05%,respectively. A dwarf mutant gene has been identified as the mutation in curl-3 leading to nucleotide conversion of C → T,and amino acid conversion of L→F. Spraying of brassinosteroid could not restore tomato growth,indicating the curl-3 mutation disrupted brassinosteroid signaling process. The ascorbic acid content in leaves and fruits of curl-3 mutant was significantly lower than those in wild-type,with a higher ratio of DHA/As A ratio. The expression of AO gene in curl-3 mutant leaves significantly increased. AO enzyme activity of curl-3 mutant leaves was significantly enhanced.