Two distinct emaraviruses,
(
) and
(
) were found to be associated with sterility mosaic disease (SMD) of pigeonpea
(L.) Millsp.. The host range of both these viruses and their vector are narrow, ...confined to
identified through mechanical transmission, and to
cvs. Top Crop, Kintoki, and Bountiful (F: Fabaceae) through mite transmission. A weed host
(F: Euphorbiaceae) was also infected and tested positive for both the viruses in RT-PCR. Among the wild
species tested,
accessions 15661, 15668, and 15671, and
accessions 15683, 15686, and 15922 were infected by both the viruses and mite vector suggesting possible sources of SMD inoculum. Though accession 15666 of
, 15696 of
, and 15639 of
were infected by both the viruses, no mite infestation was observed on them. Phylogenetic analysis of nucleotide sequences of RNA-1 and RNA-2 of
and
isolates in southern India revealed significant divergence especially
, which is closely related to the
(
) than
. In multilocation testing of pigeonpea genotypes for their broad-based resistance to SMD for two consecutive years, genotypes ICPL-16086 and ICPL-16087 showed resistance reaction (<10% incidence) in all three locations studied. Overall, the present study gives a clear idea about the host range of
and
, their molecular relationship, and sources of resistance. This information is critical for the development of reliable diagnostic tools and improved disease management strategies.
Pigeonpea Cajanus cajan (L.) Millsp. seed stored in triple layer Purdue Improved Cowpea Storage (PICS) bags for eight months retained germination and seed integrity significantly better than seed ...stored in traditional gunny bags. PICS bags prevented major damage caused by bruchids (Callosobruchus maculatus F.), while grain stored in gunny bags suffered severe losses. The aflatoxin levels in stored seed were low and not significantly different between the two storage systems. The levels of O2 in PICS bags artificially infested with C. maculatus dropped rapidly during the first month of storage while the levels of CO2 increased. Even in absence of bruchids (noninfested seed) PICS bags preserved seed germination for extended periods of time better than gunny bags; possibly due to the higher and more stable relative humidity inside the PICS bags. Higher seed germination would result in improved plant stands in the field and subsequent higher yields and increased productivity. Thus, PICS bags have shown potential to positively impact the economy of pigeonpea farmers in the semi-arid tropics.
•Storage of pigeonpea in triple-layer PICS bags prevents bruchid population expansion.•Storage in PICS bags preserves seed germination better than storage in gunny bags.•There is no significant buildup of aflatoxin levels in pigeonpea stored in PICS bags.
Aflatoxin contamination in groundnut by
Aspergillus flavus
has assumed global significance and is considered a potential threat to human and animal health. The present study focused on the screening ...and identification of stable and reliable resistance sources to pre-harvest aflatoxin contamination in ICRISAT’s groundnut mini core germplasm accessions. Field studies were conducted during 2008 and 2009 in a randomized complete block design (RCBD) with three replications. Superior accessions (
n
= 34) were selected and screened during 2010 and 2011 in a Lattice design with three replications. Seven best accessions with <1 μg kg
−1
aflatoxin B
1
levels were further selected and screened during 2012 and 2013. Based on the evaluation in 2008 and 2009, four accessions had aflatoxin contamination within 4 μg kg
−1
, 50 accessions within 10 μg kg
−1
, 66 accessions within 15 μg kg
−1
, and 75 accessions within 20 μg kg
−1
. Of the 34 selected accessions evaluated in 2010 and 2011, eight accessions had <1 μg kg
−1
. The analysis of 34 accessions over a period of four years from 2008 to 2011 indicated that the mean toxin levels ranged from 0.9 to 10.3 μg kg
−1
. In total, 31 accessions had less aflatoxin accumulation than the resistant check, 55–437. The seven best accessions, ICGs 13,603, 1415, 14,630, 3584, 5195, 6703 and 6888, over six years (2008–2013) consistently accumulated very low levels of aflatoxin (<4 μg kg
−1
). These seven accessions could be potential sources for understanding the resistant mechanisms and can be further used in developing resistant cultivars or introgressing resistance in popular released varieties.
•Aflatoxin-lys biomarker detected in 37 of 238 individuals.•10 samples had p53 mutation associated with the presence of aflatoxin-lys in human blood.•The individuals with mutation were having ...decompensated liver disease with the high (>76pg/mg of albumin) concentration of aflatoxin and also had High MELD and CTP score.•The severity of the liver disease with HBV weakly correlated with the presence and the concentration of aflatoxin-albumin adduct as well as p53 mutation at codon 249 (p=0.07).
Aflatoxin B1 is a carcinogen produced by Aspergillus flavus and a few related fungi that are often present in many food substances. It interacts synergistically with Hepatitis B or C virus (HBV, HBC) infection, thereby increasing the risk of hepatocellular carcinoma (HCC). The G to T transversion at the third position of codon 249 (AGG) of the TP53 gene, substituting arginine to serine, is the most common aflatoxin-induced mutation linked to HCC. This study examined mutations in TP53 by PCR-RFLP analysis and by measurement of an aflatoxin-albumin adduct as a biomarker for human exposure of aflatoxin B1 by indirect-competitive ELISA, in samples collected from healthy controls as well as patients with hepatitis in Hyderabad, Andhra Pradesh, India. A total of 238 blood samples were analyzed the presence of the G to T mutation. Eighteen of these samples were from HBV-positive subjects, 112 of these were from subjects who had HBV-induced liver cirrhosis, and 108 samples were taken from subjects without HBV infection or liver cirrhosis (control group). The G to T mutation was detected in 10 samples, 8 of which were from subjects positive to both HBV and aflatoxin-albumin adduct in blood (p=0.07); whilst two were from individuals who were HBV-negative, but positive for the aflatoxin-albumin adduct (p=0.14). The aflatoxin-albumin adduct was detected in 37 of 238 samples, 29 samples were from HBV-positive subjects and eight were from individuals who were positive for both HBV and the TP53 mutation (p=0.07). The concentration of aflatoxin-albumin adduct ranged from 2.5 to 667pg/mg albumin. Despite low incidence of the G to T mutation, its detection in subjects positive to aflatoxin-adducts is indicative of a strong association between the mutation and aflatoxin exposure in India.
Late leaf spot (LLS) (
Phaeoisariopsis personata
) and rust (
Puccinia arachidis
) are major foliar diseases of peanut causing significant losses worldwide. Identification and infusion of resistance ...into peanut cultivars is important in the management of these diseases. The present study therefore aimed at screening the peanut mini core collection to identify potential sources of resistance to these diseases. Two separate field experiments were conducted for screening LLS and rust under artificial epiphytotic conditions during rainy seasons of 2012 and 2013 at ICRISAT, Patancheru, India. The trials were laid in a randomized complete block design on beds with three replications. Data on LLS and rust disease severities were collected using 1 to 9 scales at 75, 90 and 105 days after sowing (DAS), and pod yields were recorded at harvest. Results indicate significant variations among accessions for LLS and rust resistance. Mean of 2 years study revealed that 53 accessions were moderately resistant (MR), 86 accessions were susceptible (S) and 45 accessions were highly susceptible (HS) to LLS. For rust disease, 10 accessions were resistant (R), 115 accessions were with ‘MR’ reaction and 59 accessions with susceptible (S) reaction. Six superior accessions in terms of combined disease resistance and yield (ICGs 4389, 6993, 11426, 4746, 6022, 11088) were selected and the disease progress curves, for each, were generated. Highest yields were recorded with ICG 11426 in LLS and rust plots. Overall, our results indicate that these six accessions can be potential sources of LLS and rust resistance.
Rice sheath blight disease （ShB）, caused by Rhizoctonia solani, gives rise to significant grain yield losses. The present study evaluated the efficacy of Integral, the commercial liquid formulation ...of Bacillus subtilis strain MBI 600, against rice ShB and for plant growth promotion. In greenhouse studies, four log concentrations of Integral （from 2.2×10^6 to 2.2×10^9 cfu/mL） were used as seed treatment （ST）. After 25 d, seedlings were dipped （SD） into Integral prior to transplanting. At 30 d after transplanting （DAT）, leaf sheaths were inoculated with immature sclerotia of the pathogen. At 45 DAT, a foliar spray （FS） with Integral was applied to some treatments. The fungicide control was 50% carbendazim at 1.0 g/L, and a nontreated control was also included. Overall, there were 10 treatments, each with five replications. ShB severity was rated at 52 DAT, and seedling height and number of tillers per plant were rated at 60 DAT. In 2009, two field trials evaluated Integral at 2.2×10^8 and 2.2×10^9 cfu/mL. Integral was applied as ST, and seedlings were produced in a nursery bed. After 32 d, seedlings were treated with Integral as SD and transplanted into 10 m^2 blocks. Foliar sprays were given at 45 and 60 DAT. There were seven treatments, each with eight replications arranged as a factorial randomized complete block design. At 20 DAT, the plots were broadcast inoculated with R. solani produced on rice grains. Seedling height before transplanting, ShB severity at 90 DAT, and grain yield at harvest were recorded. Integral at 2.2×10^9 cfu/mL provided significant increase of seedling heights over other treatments under greenhouse conditions. The Integral treatments of ST ＋ SD ＋ FS at 2.2×10^9 cfu/mL significantly suppressed ShB over other treatments. In field studies, Integral provided significant increase of seedling height in nursery, and number of tillers per plant, compared with the control. ShB severity was significantly suppressed with higher concentrations of Integral compared to lower concentrations. Grain yield were the highest at an Integral concentration of 2.2×10^9 cfu/mL. Overall, Integral significantly reduced ShB severity, enhanced seedling growth, number of tillers per plant and grain yield as ST ＋ SD ＋ FS at the concentration of 2.2×10^9 cfu/mL under the conditions evaluated.
The present study focuses on determining soil fungal community structure in different peanut-cropping sequences by using a high-resolution DNA fingerprinting technique: ribosomal intergenic spacer ...analysis (RISA). This study was initiated to determine fungal community profiles in four peanut-cropping sequences (continuous peanut, 4 years of continuous bahiagrass followed by peanut, peanut-corn-cotton, and peanut-cotton rotations), with a special focus to evaluate whether the profiles under investigation may have also indicated microbial differences that could affect Aspergillus flavus populations. Results indicated 75% similarities among fungal communities from the same cropping sequences as well as with similar times of sampling. Polymerase chain reaction (PCR)-based detection of A. flavus directly from these soils was carried out using A. flavus-specific primers (FLA1 and FLA2) and also through quantitative estimation on A. flavus and A. parasiticus agar medium. Population levels of A. flavus in soil samples ranged from zero to 1.2 × 10(3) CFU g–1 of soil (based on culturable methods); however, the fungus was not detected with A. flavus-specific primers. The minimum threshold limit at which these aflatoxin-producing fungi could be detected from the total soil genomic DNA was determined through artificial inoculation of samples with 10-fold increases in concentrations. The results indicated that a minimum population density of 2.6 × 10(6) CFU g–1 of soil is required for PCR detection in our conditions. These results are useful in further determining the relative population levels of these fungi in peanut soils with other soil fungi. This is a new approach to understanding soil fungal communities and how they might change over time and under different rotation systems.
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