| Wheat(Triticum aestivum L.)is important cultivated food crops in the world.With the increasing global food demand,improving the photosynthetic efficiency of wheat is considered to be an important method for high yield.Stomata are important channels for water vapor exchange between plant and external environment,which affects photosynthesis and transpiration of plant.ERECTA gene is an effective candidate gene for transpiration efficiency.The receptor like protein encoded by ERECTA gene regulates stomatal frequency,stomatal conductance and mesophyll cell number by interacting with EPF1,EPF2 and EPFL9,which are upstream peptide of stomatal development pathway,to affect transpiration efficiency.In this study,TaER and TaEPF/EPFL were chosen as the research objects.Wheat EPF/EPFL genes were systematically identified in genome level and some bioinformatics analysies were uesd to promote the functional analysis.Besides,haplotype analysis of transpiration efficiency major genes TaER(TaER1＿DS,TaER2＿BL)and stomatal development related gene TaEPF1-2B were used to find the relationship between haplotypes and stomatal,photosynthetic traits.And association analyse were performed to promote the photosynthetic rate and transpiration efficiency in wheat.The main results are summarized as follows:1.Genome-wide identification and expression analysis of wheat EPF / EPFL gene family.There were 35 TaEPF/EPFL genes(6 TaEPF,29 TaEPFL)identified genome widely in common wheat.Their encoded proteins belong to the extracellular secretory proteins.Most TaEPF/EPFL genes were constitutively expressed in different tissues at different stages of wheat development.The TaEPF/EPFL genes had high and specific expression in the young tissues and spikes,and some TaEPF/EPFL genes expressed in response to abiotic stresses.2.Amplification of partial TaEPF/EPFL genes and analysis of superior haplotype of TaEPF1-2B.According to the expression data,complete gene sequence of TaEPF1-2B,TaEPF1-2D,and TaEPFL9-3A were amplified to analyse the variations.There were 7 and 5 nucleotide polymorphisms detected in the coding region of TaEPF1-2B and TaEPFL9-3A.TaEPF1-2D did not detect any polymorphisms.Based on the polymorphic sites at 65 bp,158 bp and 329 bp in TaEPF1-2B,three functional markers were developed,which could separate natural populations into four haplotypes.Hap II had lower stomatal frequency and larger stomatal length and area.Besides,Hap II had significantly lower photosynthetic rate,transpiration rate and stomatal conductance at jointing stage.Hap II was the superior haplotype with low stomatal frequency.3.Polymorphism analysis of TaER genes and superior haplotype analysis of TaER1＿DS and TaER2＿BL.We selected TaER1＿BS,TaER1＿DS and TaER2＿BL sequences to analyze the nucleotide polymorphisms by re-sequencing.There was only one synonymous variation in TaER1＿BS exons,based on this developed the d CAPS marker d CAPS-3360,but the detection of natural population showed that the mutation was the rare variation.There were 1 and 6 nucleotide polymorphisms in the exons region of TaER1＿DS and TaER2＿BL,respectively.The function markers d CAPS-2307 and CAPS-8839 were developed based on those sites,d CAPS-2307 could divide natural population into two types(C and T)and CAPS-8839 could divide natural population into three types(C,T and het).The type C variation of d CAPS-2307 and type T variation of CAPS-8839 had lower stomatal frequency and larger stomatal area.d CAPS-2307-C and CAPS-8839-T were both the superior haplotype with low stomatal frequency.They had lower photosynthetic rate,transpiration rate and stomatal conductance at blooming stage,but there was no significant difference in instantaneous transpiration efficiency.In this study,we studied the relationship between candidate genes and phenotypic traits.The superior haplotypes of TaER and TaEPF/EPFL genes were identified,which provided new candidate genes for improving wheat transpiration efficiency and breeding new wheat varieties of drought-resistant and water-saving by improving stomatal traits. |
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