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Veerappan V.,Oklahoma State University | Wang J.,Cropping Systems Research Laboratory | Kang M.,Oklahoma State University | Lee J.,Oklahoma State University | And 5 more authors.
Planta | Year: 2012

Two related B3 domain transcriptional repressors, HSI2 (HIGH-LEVEL EXPRESSION OF SUGAR-INDUCIBLE GENE2)/VAL1 (VP1/ABI3-LIKE1) and HSL1 (HSI2-LIKE1)/VAL2, function redundantly to repress key transcriptional regulators of seed maturation genes in Arabidopsis thaliana seedlings. Using a forward genetic screen designed to isolate trans-acting mutants that affected expression of a transgene containing the glutathione S-transferase F8 promoter::luciferase (GSTF8::LUC) reporter, we identified a novel HSI2 mutant allele, hsi2-4, that exhibits constitutively elevated luciferase expression while expression of the endogenous GSTF8 transcript remains unchanged. The hsi2-4 lesion was found to be a missense mutation that results in the substitution of a conserved cysteine within the plant homeodomain-like (PHD) motif of HSI2. Microarray analysis of hsi2-4 and hsi2-4hsl1 mutants indicated that the HSI2 PHD-like domain functions non-redundantly to repress a subset of seed maturation genes, including those that encode AGL15 (AGAMOUS-LIKE15), FUSCA3 (FUS3), cruciferins, cupin family proteins, late-embryogenesis abundant protein, oleosins, 2S albumins and other seed-specific proteins in Arabidopsis seedlings. Many genes that are responsive to this mutation in the HSI2 PHD-like domain are enriched in histone H3 trimethylation on lysine 27 residues (H3K27me3), a repressive epigenetic mark. Chromatin immunoprecipitation analysis showed that sequences of the GSTF8::LUC transgene are enriched in H3K27me3 in a HSI2 PHD domain-dependent manner. These results indicate that the transcriptional repression activity of the HSI2 PHD domain could be mediated, at least in part, by its participation in the deposition of H3K27me3 on the chromatin of specific target genes. © 2012 Springer-Verlag.

Acosta-Martinez V.,Cropping Systems Research Laboratory | Van Pelt S.,Cropping Systems Research Laboratory | Moore-Kucera J.,Texas Tech University | Baddock M.C.,Loughborough University | Zobeck T.M.,Cropping Systems Research Laboratory
Aeolian Research | Year: 2015

Wind erosion is a threat to the sustainability and productivity of soils that takes place at local, regional, and global scales. Current estimates of the cost of wind erosion have not included the costs associated with the loss of soil biodiversity and reduced ecosystem functions. Microorganisms carried in dust are responsible for numerous critical ecosystem processes including biogeochemical cycling of nutrients, carbon storage, soil aggregation, and transformation of toxic compounds in the source soil. Currently, much of the information on microbial transport in dust has been collected at continental scales, with no comprehensive review regarding the microbial communities, particularly those associated with agricultural systems, redistributed by wind erosion processes at smaller scales including regional or field scales. Agricultural systems can contribute significantly to atmospheric dust loading and loss or redistribution of soil microorganisms are impacted in three interactive ways: (1) differential loss of certain microbial taxa depending on particle size and wind conditions, (2) through the destabilization of soil aggregates and reduction of available surfaces, and (3) through the reduction of organic matter and substrates for the remaining community. The purpose of this review is to provide an overview of dust sampling technologies, methods for microbial extraction from dust, and how abiotic, environmental, and management factors influence the dust microbiome within and among agroecosystems. The review also offers a perspective on important potential future research avenues with a focus on agroecosystems and the inclusion of the fungal component. © 2015.

Kong W.,University of Georgia | Jin H.,University of Georgia | Franks C.D.,Cropping Systems Research Laboratory | Franks C.D.,DuPont Pioneer | And 12 more authors.
G3: Genes, Genomes, Genetics | Year: 2013

We describe a recombinant inbred line (RIL) population of 161 F5 genotypes for the widest euploid cross that can be made to cultivated sorghum (Sorghum bicolor) using conventional techniques, S. bicolor × Sorghum propinquum, that segregates for many traits related to plant architecture, growth and development, reproduction, and life history. The genetic map of the S. bicolor × S. propinquum RILs contains 141 loci on 10 linkage groups collectively spanning 773.1 cM. Although the genetic map has DNA marker density well-suited to quantitative trait loci mapping and samples most of the genome, our previous observations that sorghum pericentromeric heterochromatin is recalcitrant to recombination is highlighted by the finding that the vast majority of recombination in sorghum is concentrated in small regions of euchromatin that are distal to most chromosomes. The advancement of the RIL population in an environment to which the S. bicolor parent was well adapted (indeed bred for) but the S. propinquum parent was not largely eliminated an allele for short-day flowering that confounded many other traits, for example, permitting us to map new quantitative trait loci for flowering that previously eluded detection. Additional recombination that has accrued in the development of this RIL population also may have improved resolution of apices of heterozygote excess, accounting for their greater abundance in the F5 than the F2 generation. The S. bicolor × S. propinquum RIL population offers advantages over earlygeneration populations that will shed new light on genetic, environmental, and physiological/biochemical factors that regulate plant growth and development. © 2013 Kong et al.

Reddy S.K.,Texas AgriLife Research Center | Liu S.,Texas AgriLife Research Center | Rudd J.C.,Texas AgriLife Research Center | Xue Q.,Texas AgriLife Research Center | And 6 more authors.
Journal of Plant Physiology | Year: 2014

Hard red winter wheat crops on the U.S. Southern Great Plains often experience moderate to severe drought stress, especially during the grain filling stage, resulting in significant yield losses. Cultivars TAM 111 and TAM 112 are widely cultivated in the region, share parentage and showed superior but distinct adaption mechanisms under water-deficit (WD) conditions. Nevertheless, the physiological and molecular basis of their adaptation remains unknown. A greenhouse study was conducted to understand the differences in the physiological and transcriptomic responses of TAM 111 and TAM 112 to WD stress. Whole-plant data indicated that TAM 112 used more water, produced more biomass and grain yield under WD compared to TAM 111. Leaf-level data at the grain filling stage indicated that TAM 112 had elevated abscisic acid (ABA) content and reduced stomatal conductance and photosynthesis as compared to TAM 111. Sustained WD during the grain filling stage also resulted in greater flag leaf transcriptome changes in TAM 112 than TAM 111. Transcripts associated with photosynthesis, carbohydrate metabolism, phytohormone metabolism, and other dehydration responses were uniquely regulated between cultivars. These results suggested a differential role for ABA in regulating physiological and transcriptomic changes associated with WD stress and potential involvement in the superior adaptation and yield of TAM 112. © 2014 Elsevier GmbH.

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