Identification and functional validation of a unique set of drought induced genes preferentially expressed in response to gradual water stress in peanut

Peanut, found to be relatively drought tolerant crop, has been the choice of study to characterize the genes expressed under gradual water deficit stress. Nearly 700 genes were identified to be enriched in subtractive cDNA library from gradual process of drought stress adaptation. Further, expression of the drought inducible genes related to various signaling components and gene sets involved in protecting cellular function has been described based on dot blot experiments. Fifty genes (25 regulators and 25 functional related genes) selected based on dot blot experiments were tested for their stress responsiveness using northern blot analysis and confirmed their nature of differential regulation under different field capacity of drought stress treatments. ESTs generated from this subtracted cDNA library offered a rich source of stress-related genes including signaling components. Additional 50% uncharacterized sequences are noteworthy. Insights gained from this study would provide the foundation for further studies to understand the question of how peanut plants are able to adapt to naturally occurring harsh drought conditions. At present functional validation cannot be deemed in peanut, hence as a proof of concept seven orthologues of drought induced genes of peanut have been silenced in heterologous N. benthamiana system, using virus induced gene silencing method. These results point out the functional importance for HSP70 gene and key regulators such as Jumonji in drought stress response

Delineating the structural, functional and evolutionary relationships of sucrose phosphate synthase gene family II in wheat and related grasses

<p>Abstract</p> <p>Background</p> <p>Sucrose phosphate synthase (SPS) is an important component of the plant sucrose biosynthesis pathway. In the monocotyledonous Poaceae, five <it>SPS </it>genes have been identified. Here we present a detailed analysis of the wheat <it>SPSII </it>family in wheat. A set of homoeologue-specific primers was developed in order to permit both the detection of sequence variation, and the dissection of the individual contribution of each homoeologue to the global expression of <it>SPSII</it>.</p> <p>Results</p> <p>The expression in bread wheat over the course of development of various sucrose biosynthesis genes monitored on an Affymetrix array showed that the <it>SPS </it>genes were regulated over time and space. <it>SPSII </it>homoeologue-specific assays were used to show that the three homoeologues contributed differentially to the global expression of <it>SPSII</it>. Genetic mapping placed the set of homoeoloci on the short arms of the homoeologous group 3 chromosomes. A resequencing of the A and B genome copies allowed the detection of four haplotypes at each locus. The 3B copy includes an unspliced intron. A comparison of the sequences of the wheat <it>SPSII </it>orthologues present in the diploid progenitors einkorn, goatgrass and <it>Triticum speltoides</it>, as well as in the more distantly related species barley, rice, sorghum and purple false brome demonstrated that intronic sequence was less well conserved than exonic. Comparative sequence and phylogenetic analysis of <it>SPSII </it>gene showed that false purple brome was more similar to <it>Triticeae </it>than to rice. Wheat - rice synteny was found to be perturbed at the SPS region.</p> <p>Conclusion</p> <p>The homoeologue-specific assays will be suitable to derive associations between SPS functionality and key phenotypic traits. The amplicon sequences derived from the homoeologue-specific primers are informative regarding the evolution of <it>SPSII </it>in a polyploid context.</p

Genetic diversity for grain Zn concentration in finger millet genotypes: Potential for improving human Zn nutrition

Nearly half of the world population suffers from micronutrient malnutrition, particularly Zn deficiency. It is important to understand genetic variation for uptake and translocation behaviors of Zn in relevant crop species to increase Zn concentration in edible parts. In the present study, genetic variation in grain Zn concentration of 319 finger millet genotypes was assessed. Large genetic variation was found among the genotypes, with concentrations ranging from 10 to 86 μg g− 1 grain. Uptake and translocation studies with Zn/65Zn application in 12 selected low-Zn genotypes showed wide variation in root uptake and shoot translocation, with genotypes GEC331 and GEC164 showing greater uptake and translocation. Genotypes GEC164 and GEC543 showed increased grain Zn concentration. Genotypes GEC331 and GEC164 also showed improved yield under Zn treatment. Appreciable variation in grain Zn concentration among finger millet genotypes found in this study offers opportunities to improve Zn nutrition through breeding

Differential expressed genes in A) <i>rd22-1</i> and B) <i>uspl1</i> on medium containing 150mM NaCl in the aerial part of 2 week old seedlings.

<p>Differential expressed genes in A) <i>rd22-1</i> and B) <i>uspl1</i> on medium containing 150mM NaCl in the aerial part of 2 week old seedlings.</p

Influence of drought stress treatment on single and double loss of function mutants.

<p>A) Four weeks old wild type (Col-0), single and double mutant plants (<i>rd22-1</i> and <i>uspl1, rd22-1/uspl1</i>) were drought stressed for 1–5 days before they were returned to climate chamber conditions. Time of stress treatment in days is indicated left. B) Growth rates of plants under control and drought stress conditions. Bars indicate the growth rates at 22 days after sowing (DAS) for early phase of drought stress and 34 for the late phase of drought stress. For application of drought stress stop of watering started at 21 DAS. Wild type (Col-0): green bar; <i>rd22-1</i>: bright blue bar; <i>rd22-2</i>: dark blue bar; <i>uspl1</i>: purple bar; <i>rd22-1/uspl1</i>pink bar. Original data: <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110065#pone.0110065.s005" target="_blank">Figure S5 B</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110065#pone.0110065.s009" target="_blank">Table S2</a>, Asterisks indicate significant differences (p<0.01). C) NIR reflection as a water content-related parameter. Bars indicate the NIR intensity at 21 days after sowing (DAS) for start of experiment and at 35 DAS for the end of experiment. Wild type (Col-0): green bar; <i>rd22-1</i>: bright blue bar; <i>rd22-2</i>: dark blue bar; <i>uspl1</i>: purple bar; <i>rd22-1/uspl1</i>pink bar. N_control = 5, N_stress = 10 plants. Original data in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110065#pone.0110065.s010" target="_blank">Table S3</a>.</p

<i>AtRD22</i> and <i>AtUSPL1</i>, members of the BURP gene family.

<p>A. Scheme of BURP-domain containing proteins AtRD22 and AtUSPL1. BURP (named after <u>B</u>NM2, <u>U</u>SP, <u>R</u>D22 and <u>P</u>olygalacturonase isozyme) proteins are identified by their C-terminal BURP-domain (red). The BURP domains contain 4 CH-repeats (black). In comparison to AtUSPL1, AtRD22 contains an additional motif, the TXV repeats (yellow), in AtUSPL1 no repetitive domain structure can be found. AGI ID is given in brackets. Position of T-DNA insertions for the used loss-of function mutants is indicated by a green arrow. B. Quantification of <i>AtRD22</i> and <i>AtUSPL1</i> mRNA in leaves and roots. The bar diagram indicates the amplification of <i>AtRD22</i> (left) and <i>AtUSPL1</i> mRNA relative to <i>ACT2</i> mRNA (amp. rel. to <i>ACT2</i> mRNA). Leaf (green) and root (brown) tissue of well watered and drought stressed (2% RWC) plants (N = 5) was analyzed. Asterisks indicate significant differences (T-test: *** p<0.01, ** = p<0.05).</p

Histochemical <i>ProAtUSPL1::GUS</i> activity in transgenic Arabidopsis plants.

<p>The <i>AtUSPL1</i> promoter activity was determined by histochemical localisation of GUS activity derived from the transgenic <i>ProATUSPL1::GUS</i> reporter gene. Activity indicated by blue colour can be seen in A) seedling; B) in funiculus of mature seeds; C) in flowers and stems; and D) in roots.</p