| The appropriate timing of flowering is crucial for plant reproductive success.It is therefore not surprising that intricate genetic networks have evolved to perceive and integrate both endogenous and environmental signals,such as carbohydrate and hormonal status,photoperiod and temperature.In Arabidopsis,it is knew hat FLM is a key gene for the regulation of flowering in the ambient temperature pathway.FLM was found initially four alternative splicing(?,?,? and ?)in the Wassilewskija accession,and overexpression of the FLM gene repressed flowering time in Arabidopsis.Two main FLM protein splice variants,FLM-? and FLM-?,competing for interaction with the floral repressor S VP.The SVP-FLM-? complex is formed predominately at low temperatures and prevents precociousflowering.By contrast,the competing SVP-FLM-? omplex is impaired in DNA binding and thereby indirectly promotes FT and SOC1 expression and consequently flowering at higher temperatures.At present,FLM and flowering related genes have been identified in model plant Arabidopsis,extending the study of these genes from Arabidopsis to crops could shed light on the evolution of FLM and flowering related genes in plants and inform crop breeding.Brassica rapaa isanimportant crop in Brassica genus,mainly contain Chinese cabbage(ssp.pekinensis),non-heading Chinese cabbage(ssp.chinensis),caixin(ssp.parachinensis),turnip(ssp.rapa),and oiltypes like yellow sarson(ssp.oleifera).In this study,four representative cabbage crops(caixin,Chinese cabbage,oiled type and non-heading Chinese cabbage)were pocessed by five different temperatures(16,20,24,28 and 32?)by sequencing,tissue expression,subcellular localization and CAPS labeling.Cabbage to analyze BraA.FLM.a and related flowering genes.The results are as follows:1.The flowering time of the four materials at five temperatures is different,especially on CX-58,it is early fowering at 28?and 32?.SPD1,SPD2,SPD3 and SPD4 of BraA.FLM.afour alternative splicing were amplified from CX-58 and YS-143 at 7 days after 16? treatment.Over the temperature range of 16? to 32?,the levels of the four BraA.FLM.aaltemative splicing variants of CX-58,YS-143 and CC-94 have similar patterns,steeply increasing to reach a maximum at 24?and then beingstably expressed.Expression patterns in PC-Glu are very different,as expression increases only increases after 24?,and then stays stable till 32?.Furthermore,a Pearson correlation analysis demonstrated a significant correlation between the expression data of all splicing patterns under different temperature treatments and flowering time in CX-58(r=0.50-0.68,p?0.01)and YS-143(r=0.38-0.68,p?0.01).Then we calculated the Pearson correlation between ratio SPD1/SPD4 and flowering time in CX-58(r=0.814,p?0.05)and YS-143(r=0.959,p?0.01).While these variables were not significantly correlated in CC-94 and PC-Glu.Therefore,we speculate that the alternative splicing of BraA.FLM.a may be involved in the regulation of flowering time in B.rapa.AndSPDl,may play a significant role in early flowering at low temperatures,while SPD4 may play a role in repressing flowering in CX-58 at high temperatures.2.By investigating the flowering time of early-flowering oil-type Yellow sarson,the late-flowering Vegetable turnip and the late flowering vegetable turnip and the flowering time of the F2 population,it was found that there was a significant difference in the flowering time between the two parents.We cloned the specific sequence of the BraA.FLM.a gene of the two parents and developed the CAPS marker BraA.FLM.a-Nla? at the mutation site T-A.The validation of this CAPS marker on 136 F2 isolates revealed that the flowering time of T genotype was later than that of A genotype,and there was significant difference(p<0.05).This CAPS marker BraA.FLM.a-Nla? for the BraA.FLM.a gene was found to be significantly associated with flowering time.Thus,the marker BraA.FLM.a-Nla? can be subjected to marker-assisted selection of flowering time in breeding. |
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