Serological and ecological studies ofRhizobium spp. (Cicer arietinum L.) by immunofluorescence and ELISA technique: Competitive ability for nodule formation between rhizobium strains

Summary Antisera were prepared against threeRhizobium spp, (Cicer arietinum L.) strains H45, R18 and 46b4. Results obtained by the ELISA technique complement those obtained by immunofluorescence and revealed a broad serological diversity in the chickpea Rhizobium strains used. This serological diversity allowed us to use the immunofluorescence technique for competitiveness studies between an inoculated strain (H45) and native strains. Strain H45 formed all the nodules on plants cultivated on an acidic soil, 48 per cent of Montpellier soil and 11 per cent on Montelimar soil. The inoculum concentration was 5.2 10⁷ bacteria per seed. On the Montpellier soil, the ratio of nodules formed by H45 increased with the inoculum concentration. The competitiveness of strain H45 against native strains of Montpellier soil is highly influenced by the host plant genotype. In each case, no cross reaction were observed between native strains of the soils studied and the antisera prepared against H45.

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Resume Des antiserums ont été préparés contre trois souches deRhizobium sp. du Pois chiche (Cicer arietinum L.):H45, R18 et 46b4. Les résultats obtenus en tests ELISA concordent avec ceux obtenus en immunofluorescence et révèlent une grande diversité sérologique des souches étudiées. Cette diversité sérologique a été mise à profit pour l'étude de la compétition pour la formation des nodosités entre une souche apportée au semis (H45) et les souches indigènes du sol. La souche H45 a formé la totalité des nodosités sur les plantes de pois chiche cultivées sur un sol à pH acide et respectivement 48% (sol Montpellier) et 11% (sol Montélimar) pour une concentration d'inoculum de 5, 2×10⁷ bactéries par graine. Avec le sol de Montpellier, la proportion de nodosités formées par H45 augmente avec la concentration de l'inoculum. Le pouvoir de compétition de la souche H45 vis-à-vis des souches naturelles du sol de Montpellier est fortement influencé par le génotype de la plante. Dans tous les cas, aucune réaction croisée n'est observée entre les souches indigènes des sols étudiés et l'antisérum préparé contre H45.

     

Alfalfa mosaic and cucumber mosaic virus infection in chickpea and lentil: incidence and seed transmission

Samples collected in 1994 and 1995 from commercial crops of chickpeas and lentils growing in the agricultural region of south-west Western Australia were tested for infection with alfalfa mosaic (AMV) and cucumber mosaic (CMV) viruses, and for members of the family Potyviridae using enzyme-linked immunosorbent assay (ELISA). In 1994 no virus was detected in the 21 chickpea crops tested but in 1995, out of 42 crops, AMV was found in two and CMV in seven. With lentils, AMV and/or CMV was found in three out of 14 crops in 1994 and 4 out of 13 in 1995, both viruses being detected in two crops in each year. Similar tests on samples from chickpea and lentil crops and plots growing at experimental sites, revealed more frequent infection with both viruses. No potyvirus infection was found in chickpeas or lentils in agricultural areas either in commercial crops or at experimental sites. However, bean yellow mosaic virus (BYMV) was detected along with AMV and CMV in irrigated plots of chickpeas and lentils at a site in Perth. When samples of seed from infected crops or plots of chickpeas and lentils were germinated and leaves or roots of seedlings tested for virus infection by ELISA, AMV and CMV were found to be seed-borne in both while BYMV was seed-borne in lentils. The rates of transmission found through seed of chickpea to seedlings were 0.1–1% with AMV and 0.1–2% with CMV. Seed transmission rates with lentil were 0.1–5% for AMV, 0.1–1% for CMV and 0.8% for BYMV. Individual seed samples of lentil and chickpea sometimes contained both AMV and CMV. With both species, infection with AMV and CMV was sometimes found in commercial seed stocks or seed stocks from multiplication crops of advanced selections nearing release as new cultivars. Seed-borne virus infection has important practical implications, as virus sources can be re-introduced every year to chickpea and lentil crops or plots through sowing infected seed stocks leading to spread of infection by aphid vectors, losses in grain yield and further contamination of seed stocks.     

Interaction of Fusarium oxysporum f. sp. ciceri and Meloidogyne javanica on Cicer arietinum

Interaction of Meloidogyne javanica and Fusarium oxysporum f. sp. ciceri was studied on Fusarium wilt-susceptible (JG 62 and K 850) and resistant (JG 74 and Avrodhi) chickpea cultivars. In greenhouse experiments, inoculation of M. javanica juveniles prior to F. oxysporum f. sp. ciceri caused greater wilt incidence in susceptible cultivars and induced vascular discoloration in roots of resistant cultivars. Nematode reproduction was greatest (P = 0.05) at 25 °C. Number of galls and percentage of root area galled increased when the temperature was increased from 15 °C to 25 °C. Wilt incidence was greater at 20 °C than at 25 °C. Chlorosis of leaves and vascular discoloration of plants did not occur at 15 °C. The nematode enhanced the wilt incidence in wilt-susceptible cultivars only at 25 °C. Interaction between the two pathogens on shoot and root weights was significant only at 20 °C, and F. o. ciceri suppressed the nematode density at this temperature. Wilt incidence was greater in clayey (48% clay) than in loamy sand (85% sand) soils. The nematode caused greater plant damage on loamy sand than on clayey soil. Fusarium wilt resistance in Avrodhi and JG 74 was stable in the presence of M. javanica across temperatures and soil types.     

Characterisation of Phosphate Solubilising Bacteria in Sandy Loam Soil Under Chickpea Cropping System

With the aim to explore the possible role of phosphate-solubilizing bacteria (PSB) in phosphorus (P) cycling in agricultural soils, we isolated PSB inhabiting naturally in the sandy loam soils under chickpea cropping of Patiala (Punjab State). A total of 31 bacterial isolates showing solubilizing activities were isolated on Pikovskaya agar plates. The potent phosphate solubilizers were selected for further characterization. These isolates were shown to belong to the genera Pseudomonas and Serratia by partial sequencing analysis of their respective 16S rDNA genes. ERIC-PCR based fingerprinting was done for tracking the survival of introduced populations of the PSB during mass inoculation of these strains under chickpea plots. The results showed positive correlation (r² = 0.853) among soil phosphatase activity and phosphate solubilizers population, which was also positively correlated (r² = 0.730) to available phosphorus. Identification and characterization of soil PSB for the effective plant growth-promotion broadens the spectrum of phosphate solubilizers available for field application.     

Integrated Seed Proteome and Phosphoproteome Analyses Reveal Interplay of Nutrient Dynamics,Carbon–Nitrogen Partitioning,and Oxidative Signaling in Chickpea

Nutrient dynamics in storage organs is a complex developmental process that requires coordinated interactions of environmental, biochemical, and genetic factors. Although sink organ developmental events have been identified, understanding of translational and post‐translational regulation of reserve synthesis, accumulation, and utilization in legumes is limited. To understand nutrient dynamics during embryonic and cotyledonary photoheterotrophic transition to mature and germinating autotrophic seeds, an integrated proteomics and phosphoproteomics study in six sequential seed developmental stages in chickpea is performed. MS/MS analyses identify 109 unique nutrient‐associated proteins (NAPs) involved in metabolism, storage and biogenesis, and protein turnover. Differences and similarities in 60 nutrient‐associated phosphoproteins (NAPPs) containing 93 phosphosites are compared with NAPs. Data reveal accumulation of carbon–nitrogen metabolic and photosynthetic proteoforms during seed filling. Furthermore, enrichment of storage proteoforms and protease inhibitors is associated with cell expansion and seed maturation. Finally, combined proteoforms network analysis identifies three significant modules, centered around malate dehydrogenase, HSP70, triose phosphate isomerase, and vicilin. Novel clues suggest that ubiquitin–proteasome pathway regulates nutrient reallocation. Second, increased abundance of NAPs/NAPPs related to oxidative and serine/threonine signaling indicates direct interface between redox sensing and signaling during seed development. Taken together, nutrient signals act as metabolic and differentiation determinant governing storage organ reprogramming.     

Phylogenetic analysis in the genus Cicer and cultivated chickpea using RAPD and ISSR markers

Seventy five accessions belonging to 14 species of the genus Cicer were analysed with PCR-based molecular markers to determine their phylogenetic relationships. Eight of the species were annuals and included the Section Monocicer which contains cultivated chickpea (Cicer arietinum L.). The remaining six species were perennials (five from Section Polycicer and one from Section Acanthocicer). More than one accession per species was analysed in most of the wild species; within C. arietinum, 26 accessions including Kabuli and Desi types, were studied. RAPD analyses using 12 primers gave 234 polymorphic fragments. Variability within species was detected. A dendrogram based on the Jaccard similarity index showed that the distribution pattern of variability between species was related to both growth habit and geographical origin. An accession of Cicer reticulatum was closer to accessions of Cicer echinospermum than to the four remaining of C. reticulatum, suggesting the possibility of gene flow between species. Cluster analysis for cultivated chickpea differentiated Kabuli and Desi types but we did not detect a clear relationship between groups and the geographical origin of the accessions. Received: 5 April 2001 / Accepted: 13 July 2001     

应用SSR标记分析鹰嘴豆种质资源遗传多样性

种质资源的遗传多样性是育种工作的基础,本研究利用SSR标记对鹰嘴豆资源进行遗传多样性分析,旨在发掘鹰嘴豆资源中丰富的遗传变异。从48对鹰嘴豆SSR引物中筛选出18对核心多态性引物,对96份不同来源的鹰嘴豆种质资源进行SSR标记的遗传多样性分析。结果表明,18对SSR引物共检测到115个等位变异,占总检测位点的52.99%,每对SSR引物可检测出3~10个等位变异,平均6.39个;平均每个位点多态信息量(PIC)为0.8107,变化范围为0.6661~0.8984。Shannon's信息指数平均为1.4769,变化范围为0.0607~1.9584。PGMA聚类结果表明,在遗传相似系数0.59处,可将96份鹰嘴豆资源分为6个类群,类群Ⅰ包含9份资源,类群Ⅱ包含2份资源,类群Ⅲ包含28份资源,类群Ⅳ包含4份资源,类群Ⅴ包含40份资源,类群Ⅵ包含13份资源。本研究对我国鹰嘴豆种质资源的评价与利用、优异基因的挖掘、育种亲本材料的选择等提供科学依据。     

Effects of selection criteria on yield stability in chickpea (Cicer arietinum L.)

Summary Selection in the F₃ generation for seed yield, fruiting branches/plant, effective pods/plant, and seed index (100-seed weight) was carried out in two chickpea crosses. Sixty F₅ lines (15 lines/selection criterion) along with check variety were evaluated for seed yield in three distinct environments. The effects of selection criteria on yield stability was examined using linear regression approach and genotype-grouping technique. There were no differences between selection criteria for linear yield responses of F₅ lines to different environments. Within all four selection criteria the lines showed similar linear responses. The non-linear component was relatively higher for lines selected for effective pods and seed index than lines selected for yield and fruiting branches. On the basis of mean yield and coefficient of variation across environments, the seed index was the least effective selection criterion for developing high yielding and stable lines. When the results of stability parameters and genotype-grouping technique were considered together, selection for yield and fruiting branches was highly effective for isolating stable and high yielding lines.     

Characterization of genetic diversity in chickpea using SSR markers,Start Codon Targeted Polymorphism (SCoT) and Conserved DNA-Derived Polymorphism (CDDP)

Physiology and Molecular Biology of Plants - To evaluate the genetic diversity among 48 genotypes of chickpea comprising cultivars, landraces and internationally developed improved lines genetic...