Project Number: 5366-21000-030-00
Start Date: Feb 06, 2013
End Date: Feb 05, 2018
Sub-objective 1.1: Hypothesis: Barley MAz423 is a novel “high seed total P” mutant with no impact on yield. Analyses of barely MAz423 will define mode of inheritance, confirmation of seed P phenotype and correlation or lack with seed yield. If warranted, mapping and gene identification will proceed. Studies of additional barley lpa mutants will continue. Sub-objective 1.2: Hypotheses: Barley lpa1 encodes a novel seed P transporter important to phytic acid and total P. “Complementation” and “knock-out” will determine if the putative P transporter is the gene perturbed in barley lpa1. New recessive alleles of the transporter in both barley and maize will be isolated using “TILLING”. Analyses of these new alleles will determine if the barley lpa1 phenotype can be engineered in maize. Sub-objective 1.3: Hypothesis: We can isolate alleles that impact seed total P but have little or no impact on maternal plant P. Chemically-mutagenized maize and barley populations will be screened for mutations that perturb seed total P amount and distribution. Genetics and inheritance of selected mutations will be studied in greater detail to identify those that perturb seed P without perturbing maternal plant P. Sub-objective 2.1: Hypothesis: Epigenetic silencing at lpa1 occurs both spontaneously and via paramutation. Analyses will describe the occurrence of these phenomena at maize lpa1, defining rate and critical sequences/modifications. Next-generation sequencing combined with bisulfite sequencing will be used in mapping/sequencing cytosine methylation and sequence changes and additional methods will be used to study histone modification. Sub-objective 2.2: Hypotheses: heritable plant growth phenotype changes and other molecular adaptations, in response to environmental stresses such as P nutrient deficiency, will be observed with barley and can be used to develop lines more productive under nutrient or other stress. Plants will be grown to maturity under various P nutritional or other stresses, and the seed they produce will be used to study inheritance of growth habit and molecular adaptations. The genetic versus epigenetic contribution to heritable adaptive responses will be determined using current methods including high-throughput, low-cost next-generation sequencing. Sub-objective 2.3: Hypotheses: Heritable epigenetic change contributes substantially to gains due to recurrent selection; recurrent selection for yield or stress tolerance can substantially enhance performance of low-phytate lines. Various recurrent selection schemes for performance under field conditions or under experimentally-induced abiotic stress, will be conducted with sets of barley low phytic acid isolines. Gain-due-to-selection for various performance parameters will be quantitated. Current methods of such as mapping-by-sequencing and techniques including bulked-segregant analyses, low-cost high-throughput next-generation sequencing, bisulfite sequencing, and sample multiplexing will be used to quantitate the contribution of genetic versus epigenetics to gain-due-to-selection.