Phosphorus use efficiency in wheat and identification of the associated genes
Loading...
Date
2017
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Punjab Agricultural University, Ludhiana
Abstract
Agriculturally, phosphorus (P) is the second most essential element for the growth and development of the crop; due to its key role in various biochemical reactions in the plant system such as phosphorylation, DNA replication, membrane formation, etc. The population boom demanding a leap in the quantum of production of food grains increases the need for the external application of the nutrients in the form of fertilizers. Phosphatic fertilizers being the costliest among all the chemical fertilizers makes it difficult for a marginal farmer to meet his farm demands. This situation could be managed by breeding crops which would use phosphorus efficiently. A panel of 42 wheat genotypes consisting of 10 bread wheat genotypes, 16 synthetic wheat and 16 Triticum dicoccoides accessions was assembled for assessing phosphorus use efficiency and underlying genes. Thirty of these genotypes were analysed in a pot experiment at two Phosphorus treatments. The panel was evaluated for various agro-morphological traits such as phosphorus concentration in straw and seeds, shoot dry matter, number of grains and yield and Phosphorus deficiency tolerance index (PDTI) of every trait was determined for the panel. The synthetic wheat PBW114-Ae.tauschii acc. pau14200 was found to be an efficient genotype at phosphorus starvation as its relative growth at phosphorus starvation was 68.5%, 66.2%, 92.1% and 151.1% more in case of shoot dry matter, number of tillers, yield and number of grains per plant, respectively. T. dicoccoides were observed to be better at Phosphorus uptake as compared to other genotypes. In rice OsPstol1(Phosphorus starvation tolerance), a gene for phosphorus use efficiency, has been cloned and characterized which is responsible for a three-fold increase in phosphorus-uptake and grain-yield in rice. A similarity search was conducted in the wheat genome sequence (IWGSC) for the OsPstol1 orthologous sequences which led to identification of six homologous sequences, two at chromosome 5AS, one each on 3B, 3AL, 3DL and 6DS. Genes were predicted and primers were designed for in vitro amplification and matching transcripts for these sequences were mined from wheat transcriptome database from a Phosphorus starvation study. Amplifications in the germplasm panel showed the presence of homologous sequences in most of the genotypes. Investigation was proceeded with the first hit contig of the BLAST result ‘5AS_IWGSC_1484262’ for allele mining which resulted in the identification of seven SNPs forming five haplotypes which further translated to four different polypeptide sequences. The synthetic wheat PBW114-Ae.tauschii acc. pau14200 could be a source for the genes responsible for enhanced phosphorus use efficiency in wheat and its relation with the wheat orthologs of OsPstol1 could be deduced by further investigating through expression analysis and the promoter sequence analysis of the ortholog.
Description
Keywords
null