Effect of water regimes on seed quality parameters of rice (Oryza sativa L.) grown under aerobic and wetland conditions

A field experiment was conducted to know the effect of water regimes on seed quality parameters of rice and the was conducted by using factorial randomized complete block design, with two genotypes (BI-33 and Jaya) and two planting methods (Aerobic and Wetland). The resultants seeds were taken to conduct laboratory experiments pertaining to seed quality attributes and the studies revealed that the BI-33 under aerobic condition had shown a significantly higher seed quality with respect to germination (99%), mean seedling length (26.75cm), seedling dry weight (10.42 mg), SVI-I (2648) and SVI-II (1032) , highest total dehydrogenase activity (0.53 OD @ 480nm), highest amylase activity (14.67 %), highest total soluble protein content (7.15%) and recorded less EC (70.95 ?Sm-1/ppm). The experimental results revealed that both the genotypes and method of planting contribute for seed quality of the genotypes which were grown under different water regimes. The genotype grown under aerobic condition was better in seed quality parameters compared to wetland condition

Genetic variability on leaf morpho-anatomical traits in relation to sterility mosaic disease (SMD) resistance in pigeonpea

Abstract Sterility mosaic disease (SMD) is a major biotic constraint in almost all pigeonpea growing areas caused by eriophyid mite transmitted pigeonpea sterility mosaic virus (PPSMV). Direct selection for resistance to SMD is expensive and laborious as it requires dependent of sick plots. Identification of easily assayable and simply inherited morphological traits such as leaf anatomical traits would enable increased efficiency of breeding pigeonpea for SMD resistance. A set of 70 pigeonpea accessions were evaluated for 12 leaf structural features such as leaf thickness (LT), upper epidermal thickness (UEPT), lower epidermal thickness (LEPT), upper cuticle cell wall complex (UCWC), lower cuticle cell wall complex (LCWC), trichome number on upper surface of leaf (TNUS), trichome number on lower surface of leaf (TNLS), trichome length on upper surface of leaf (TLUS) and on lower surface of leaf (TLLS) at experimental plots of Zonal Agricultural Research Station (ZARS), UAS, Bengaluru. The accessions differed significantly for most of the traits except for specific leaf area (SLA) and specific leaf weight (SLW). The accessions were grouped into four clusters, with significant differences in cluster means and variances. Principal component analysis (PCA) showed first three PCs explaining 69.70 % of the total variation and morpho-anatomical traits such as leaf thickness (LT), trichome length on upper (TLUS) and lower (TLLS) surface of leaf were the most important characters for disease incidence. Furthermore, correlation of all the leaf traits in relation to percent incidence (PDI) indicated only TLLS having significant negative correlation (-0.456*) with SMD incidence. While, trichome length also showed higher phenotypic (PCV) and genotypic (GCV) coefficient of variation 34.33 and 34.02, respectively and broad senesce heritability (98.2%) coupled with high genetic advance (69.45). Therefore, breeding for trichome length is very important to impart vector resistance. This may provide broad based resistance to all the isolates of SMD in pigeonpea

Water uptake dynamics under progressive drought stress in diverse accessions of the OryzaSNP panel of rice (Oryza sativa)

In addition to characterising root architecture, evaluating root water uptake ability is important for understanding drought response. A series of three lysimeter studies were conducted using the OryzaSNP panel, which consists of 20 diverse rice (Oryza sativa L.) genotypes. Large genotypic differences in drought response were observed in this genotype panel in terms of plant growth and water uptake. Total water uptake and daily water uptake rates in the drought-stress treatment were correlated with root length density, especially at depths below 30 cm. Patterns of water uptake among genotypes remained consistent throughout the stress treatments: genotypes that initially extracted more water were the same genotypes that extracted more water at the end of the study. These results suggest that response to drought by deep root growth, rather than a conservative soil water pattern, seems to be important for lowland rice. Genotypes in the O. sativa type aus group showed some of the greatest water uptake and root growth values. Since the OryzaSNP panel has been genotyped in detail with SNP markers, we expect that these results will be useful for understanding the genetics of rice root growth and function for water uptake in response to drought

Theory of Cylindrical Tubules and Helical Ribbons of Chiral Lipid Membranes

We present a general theory for the equilibrium structure of cylindrical tubules and helical ribbons of chiral lipid membranes. This theory is based on a continuum elastic free energy that permits variations in the direction of molecular tilt and in the curvature of the membrane. The theory shows that the formation of tubules and helical ribbons is driven by the chirality of the membrane. Tubules have a first-order transition from a uniform state to a helically modulated state, with periodic stripes in the tilt direction and ripples in the curvature. Helical ribbons can be stable structures, or they can be unstable intermediate states in the formation of tubules.Comment: 43 pages, including 12 postscript figures, uses REVTeX 3.0 and epsf.st

Regular dendritic patterns induced by non-local time-periodic forcing

The dynamic response of dendritic solidification to spatially homogeneous time-periodic forcing has been studied. Phase-field calculations performed in two dimensions (2D) and experiments on thin (quasi 2D) liquid crystal layers show that the frequency of dendritic side-branching can be tuned by oscillatory pressure or heating. The sensitivity of this phenomenon to the relevant parameters, the frequency and amplitude of the modulation, the initial undercooling and the anisotropies of the interfacial free energy and molecule attachment kinetics, has been explored. It has been demonstrated that besides the side-branching mode synchronous with external forcing as emerging from the linear Wentzel-Kramers-Brillouin analysis, modes that oscillate with higher harmonic frequencies are also present with perceptible amplitudes.Comment: 15 pages, 23 figures, Submitted to Phys. Rev.

Environmental Response and Genomic Regions Correlated with Rice Root Growth and Yield under Drought in the OryzaSNP Panel across Multiple Study Systems

Funding: This research was funded by the Generation Challenge Program (GCP) project G3008.06, “Targeting Drought-Avoidance Root Traits to Enhance Rice Productivity under Water-Limited Environments". The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

SSeCKS/Gravin/AKAP12 attenuates expression of proliferative and angiogenic genes during suppression of v-Src-induced oncogenesis

BACKGROUND: SSeCKS is a major protein kinase C substrate with kinase scaffolding and metastasis-suppressor activity whose expression is severely downregulated in Src- and Ras-transformed fibroblast and epithelial cells and in human prostate, breast, and gastric cancers. We previously used NIH3T3 cells with tetracycline-regulated SSeCKS expression plus a temperature-sensitive v-Src allele to show that SSeCKS re-expression inhibited parameters of v-Src-induced oncogenic growth without attenuating in vivo Src kinase activity. METHODS: We use cDNA microarrays and semi-quantitative RT-PCR analysis to identify changes in gene expression correlating with i) SSeCKS expression in the absence of v-Src activity, ii) activation of v-Src activity alone, and iii) SSeCKS re-expression in the presence of active v-Src. RESULTS: SSeCKS re-expression resulted in the attenuation of critical Src-induced proliferative and pro-angiogenic gene expression including Afp, Hif-1α, Cdc20a and Pdgfr-β, and conversely, SSeCKS induced several cell cycle regulatory genes such as Ptpn11, Gadd45a, Ptplad1, Cdkn2d (p19), and Rbbp7. CONCLUSION: Our data provide further evidence that SSeCKS can suppress Src-induced oncogenesis by modulating gene expression downstream of Src kinase activity

Environmental Response and Genomic Regions Correlated with Rice Root Growth and Yield under Drought in the OryzaSNP Panel across Multiple Study Systems

The rapid progress in rice genotyping must be matched by advances in phenotyping. A better understanding of genetic variation in rice for drought response, root traits, and practical methods for studying them are needed. In this study, the OryzaSNP set (20 diverse genotypes that have been genotyped for SNP markers) was phenotyped in a range of field and container studies to study the diversity of rice root growth and response to drought. Of the root traits measured across more than 20 root experiments, root dry weight showed the most stable genotypic performance across studies. The environment (E) component had the strongest effect on yield and root traits. We identified genomic regions correlated with root dry weight, percent deep roots, maximum root depth, and grain yield based on a correlation analysis with the phenotypes and aus, indica, or japonica introgression regions using the SNP data. Two genomic regions were identified as hot spots in which root traits and grain yield were co-located; on chromosome 1 (39.7–40.7 Mb) and on chromosome 8 (20.3–21.9 Mb). Across experiments, the soil type/ growth medium showed more correlations with plant growth than the container dimensions. Although the correlations among studies and genetic co-location of root traits from a range of study systems points to their potential utility to represent responses in field studies, the best correlations were observed when the two setups had some similar properties. Due to the co-location of the identified genomic regions (from introgression block analysis) with QTL for a number of previously reported root and drought traits, these regions are good candidates for detailed characterization to contribute to understanding rice improvement for response to drought. This study also highlights the utility of characterizing a small set of 20 genotypes for root growth, drought response, and related genomic regions

Methodologies for root drought studies in rice

vii, 65 p. : ill.; 26 c

Comparative Genomics of the Genomic Region Controlling Resistance to Puccinia Polysora Underw. in Zea Mays L.

Polysora rust (Southern Corn Rust) is a majordisease of maize in tropical and subtropical regioncausing yield loss in excess of 45%. The loci governingresistance (Rpp9, RppQ and RppD) have been mapped to10.01 bins on short arm of maize chromosome 10, whichalso has genes for common rust resistance like Rp1 andRp5. With the publication of maize draft genomicsequence we tried to annotate the region spanning thesegenes using comparative genomic tools. We constructed aphysical map using the various loci and thecorresponding markers, BAC clones and contigs reportedfrom the previous researchers and using MaizeGDB. Thesequence for this region was downloaded frommaizesequence.org. The sequence was scanned for codingregions using GENSCAN and the CDS and peptidesobtained along with the whole sequence (in bits of 1 MB)was subjected to BLAST analysis in NCBI-nBLAST,NCBI-pBLAST, COGE-BLAST and MaizeGDB BLAST.The region when located on a physical map, had all theloci governing Polysora rust resistance in a overlappingposition and was around 3 MB size. Two loci RppQ andRppD covered large portion of the 3MB region whereasRpp9 was 82769 bp long. The BLAST results indicatedthe similarity of the region to many loci responsible fordisease resistance like PR protein, Serine/threoninekinase protein, rust resistance protein (rp3-1), receptorkinases and zein cluster. The region shared homologywith rice, sorghum and brachypodium grass and wefound some orthologs having NB-LRR domain. Hencefrom this analysis it could be concluded that the region isresponsible for disease resistance and host many othergenes linked with resistance to various diseases