Pigeonpea Sterility Mosaic Disease Research Articles

Assessment of the spatial distribution and identification of potential risk areas for the sterility mosaic disease of pigeonpea (Cajanus cajan L. Huth) in Southern India

Sterility mosaic disease (SMD) is an emerging biotic risk to the cultivation of pigeonpea throughout the Indian subcontinent. The prevalence and distribution of SMD documented from diverse agro-climatic zones are still poorly known. In this investigation, we determined the spatial distribution of SMD covering major pigeonpea-growing states of Southern India namely, Karnataka, Telangana, Tamil Nadu, Maharashtra, and Andhra Pradesh by considering 2 years of exploratory survey data. Geospatial approaches were employed to determine the SMD incidence levels at unvisited locations using neighboring observations. The results indicated enormous variability in disease incidence ranging from 0 to 82.64% and 0 to 36.84%, respectively, in Kharif 2021–22 and 2022–23 in pigeonpea-growing states. Spatial autocorrelation analysis and Ripley’s K function established the presence of average clustering over sampling locations. Two main clusters were identified via agglomerative hierarchical cluster analysis. From the Local Moran’s I spatial autocorrelation (LISA) analysis, most of the districts were clustered together at (I<0). From the p-values, Bidar and Krishnagiri districts recorded the highest spatial dependence, while the remaining districts recorded medium spatial dependence (p < 0.05). Based on kriging, the Chittoor district of Andhra Pradesh, Medak and Ranga Reddy districts of Telangana, Bijapur district of Karnataka, and Latur district in Maharashtra states were found to be vulnerable to SMD occurrence in the future. The Matern and Spherical models were shown to be the best of the several semivariogram experimental models tested for spatial patterns of SMD incidence, from which OK and IK maps were created. Based on the interpolation results, the potential SMD hotspots/risk areas were most prominent in Telangana, Andhra Pradesh, Karnataka, and Tamil Nadu states. These identified hotspots for SMD revealed high levels of disease probability rates (>25%) above the threshold level and must be closely monitored to restrict and minimize further disease spread across the studied areas in Southern India. In pigeonpea, this is the first study in India that attempted to understand the spatial pattern of SMD using geostatistical methodologies. The results of the study will aid in the design and dissemination of specific management practices and curb the further spread of SMD.

Evaluation of Pigeonpea Genotypes against Sterility Mosaic Disease

Pigeonpea (Cajanus cajan L.) belonging to family Leguminosae is an important leguminous pulse crop of semi-arid tropic and subtropic regions (Asia and Africa). It is also known as red gram, arhar, tur dal. The crop is affected by several phytopathogens, of which, pigeonpea sterility mosaic disease/virus, and transmissible by eriophyid mites (Aceria cajani) has been a major bottleneck. Yield losses up to 95 per cent or even 100 per cent in severe Sterility Mosaic Disease incidence were reported. Therefore, present investigation on screening of pigeon pea genotypes against the sterility mosaic disease was carried out during Kharif, 2018 at the Department of Plant Pathology, College of Agriculture, Latur. In present study, about 27 entries of pigeonpea were screened under natural epiphytotic against pigeonpea sterility mosaic disease. Of these GRG-152, ICP-2376, BRG-5, BRG-4, ICPL-15048, BSMR853, BSMR-736, BRG-1and BRG-3 were resistant; MPV-106, RVSA-16-1, IPA-16-8 and BRG-2 were moderately resistant, whereas, PUSA-2017-01, TDRG-58, ICP-8863, PUSA-2018, PUSA-2018-1, PUSA-2018-2, PUSA-2018-3 ,PUSA-2018-5, AKTE-12-04, KRG-244, PADT-16, RKPV-912, JKM-189 and TJT-501 were susceptible to Sterility Mosaic disease.

Salient Findings on Host Range, Resistance Screening, and Molecular Studies on Sterility Mosaic Disease of Pigeonpea Induced by Pigeonpea sterility mosaic viruses (PPSMV-I and PPSMV-II).

Two distinct emaraviruses, Pigeonpea sterility mosaic virus-I (PPSMV-I) and Pigeonpea sterility mosaic virus-II (PPSMV-II) were found to be associated with sterility mosaic disease (SMD) of pigeonpea [Cajanus cajan (L.) Millsp.]. The host range of both these viruses and their vector are narrow, confined to Nicotiana benthamiana identified through mechanical transmission, and to Phaseolus vulgaris cvs. Top Crop, Kintoki, and Bountiful (F: Fabaceae) through mite transmission. A weed host Chrozophora rottleri (F: Euphorbiaceae) was also infected and tested positive for both the viruses in RT-PCR. Among the wild Cajanus species tested, Cajanus platycarpus accessions 15661, 15668, and 15671, and Cajanus scarabaeoides accessions 15683, 15686, and 15922 were infected by both the viruses and mite vector suggesting possible sources of SMD inoculum. Though accession 15666 of C. platycarpus, 15696 of C. scarabaeoides, and 15639 of Cajanus lanceolatus 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 PPSMV-I and PPSMV-II isolates in southern India revealed significant divergence especially PPSMV-II, which is closely related to the Fig mosaic virus (FMV) than PPSMV-I. 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 PPSMV-I and PPSMV-II, their molecular relationship, and sources of resistance. This information is critical for the development of reliable diagnostic tools and improved disease management strategies.

Ascertaining sources of resistance against fusarium wilt and sterility mosaic disease of pigeonpea

Ascertaining sources of resistance against fusarium wilt and sterility mosaic disease of pigeonpea

Prevalence of sterility mosaic disease (SMD) and variability in pigeonpea sterility mosaic virus (PPSMV) in southern-India

Sterility mosaic disease (SMD) is a major problem for pigeonpea production in the Indian subcontinent. A comprehensive and systematic survey was carried out to determine the incidence of pigeonpea sterility mosaic disease (SMD) and variability among disease causing agents in Andhra Pradesh, Karnataka, Tamil Nadu and Telangana states of southern India during the 2017 rainy season. The results indicate a huge variation in SMD incidence ranging from 0 to 47.50% among the surveyed states and also within the states. Further, the phylogenetic analysis of the RNA-3 sequence of disease causing two viral agents such as PPSMV-I and PPSMV-II exhibited considerable variability among seven different geographical strains representing four states in southern India. RNA-3 sequence of PPSMV-I of Bengaluru, Tirupathi, Vamban, and Coimbatore isolates clustered together, while Gulbarga isolate distinctly separated out. Similarly, a RNA-3 sequence of PPSMV-II of Vamban isolate was separated out from the rest of the cluster. There is a separate existence of PPSMV-II alone alongside mixed infection of PPSMV-I and PPSMV-II in southern India. The samples from Patancheru location were positive for PPSMV-I and PPSMV-II, whereas one sample from Bengaluru and four samples from Coimbatore location were found positive for PPSMV-II only and the rest of the samples were positive for both the viruses. None of the sample was positive for PPSMV-I alone. Overall our study provides evidence of variability in SMD causing agents which is critical in developing precise diagnostic tools and stable management strategies in pigeonpea.

Evaluation of pigeonpea (Cajanus cajan) genotypes against pigeonpea sterility mosaic disease

Evaluation of pigeonpea (<i>Cajanus cajan)</i> genotypes against pigeonpea sterility mosaic disease

Role of leaf morphology in defense against sterility mosaic disease of pigeonpea

Role of leaf morphology in defense against sterility mosaic disease of pigeonpea

Molecular characterization of emaraviruses associated with Pigeonpea sterility mosaic disease

Sterility Mosaic Disease (SMD) of pigeonpea (Cajanus cajan (L.) Millspaugh) is a complex disease due to various factors including the presence of a mixed infection. Comparison of dsRNA profile and small RNA (sRNA) deep sequencing analysis of samples from three locations revealed the presence of Pigeonpea sterility mosaic virus-I and II (PPSMV-I and II) from Chevella and only PPSMV-II from Bengaluru and Coimbatore. PPSMV-I genome consisted of four while PPSMV-II encompassed six RNAs. The two viruses have modest sequence homology between their corresponding RNA 1–4 encoding RdRp, glycoprotein precursor, nucleocapsid and movement proteins and the corresponding orthologs of other emaraviruses. However, PPSMV-II is more related to Fig mosaic virus (FMV) than to PPSMV-I. ELISA based detection methodology was standardized to identify these two viruses, uniquely. Mite inoculation of sub-isolate Chevella sometimes resulted in few- to- many pigeonpea plants containing PPSMV-I alone. The study shows that (i) the N-terminal region of RdRp (SRD-1) of both the viruses contain “cap-snatching” endonuclease domain and a 13 AA cap binding site at the C-terminal, essential for viral cap-dependent transcription similar to the members of Bunyaviridae family and (ii) P4 is the movement protein and may belong to ‘30 K superfamily’ of MPs.

Variability of Emaravirus Species Associated with Sterility Mosaic Disease of Pigeonpea in India Provides Evidence of Segment Reassortment.

Sterility mosaic disease (SMD) of pigeonpea is a serious constraint for cultivation of pigeonpea in India and other South Asian countries. SMD of pigeonpea is associated with two distinct emaraviruses, Pigeonpea sterility mosaic virus 1 (PPSMV-1) and Pigeonpea sterility mosaic virus 2 (PPSMV-2), with genomes consisting of five and six negative-sense RNA segments, respectively. The recently published genome sequences of both PPSMV-1 and PPSMV-2 are from a single location, Patancheru from the state of Telangana in India. However, here we present the first report of sequence variability among 23 isolates of PPSMV-1 and PPSMV-2, collected from ten locations representing six states of India. Both PPSMV-1 and PPSMV-2 are shown to be present across India and to exhibit considerable sequence variability. Variability of RNA3 sequences was higher than the RNA4 sequences for both PPSMV-1 and PPSMV-2. Additionally, the sixth RNA segment (RNA6), previously reported to be associated with only PPSMV-2, is also associated with isolates of PPSMV-1. Multiplex reverse transcription PCR (RT-PCR) analyses show that PPSMV-1 and PPSMV-2 frequently occur as mixed infections. Further sequence analyses indicated the presence of reassortment of RNA4 between isolates of PPSMV-1 and PPSMV-2.

Management of pigeonpea sterility mosaic disease

Field experiments were conducted to ascertain the efficacy of leaf extracts from botanical species viz., Vitex negundo (10%), Psoralea corylifola (10 %), Winter Green oil 30 EC (2%) against Sterility Mosaic Disease (SMD) in pigeonpea under field conditions. Resistant inducing chemicals viz., 200 ppm Salicylic acid and acaricides viz ; 0 .1% Fenazaquin and 0. 2% Dicofol were also evaluated against SMD. Comprehensive analysis of data demonstrated that the two sprays of 0.1% Fenazaquin first at 30 days after sowing and second at 15 days after first spray recorded the lowest (8.8 per cent) SMD incidence as compared to 46.1 per cent in untreated control which accounted for the disease reduction of 80.9 per cent. Among the plant products tested, winter green oil 30 EC (2 %) was effective by recording 19.0 per cent SMD incidence with 58.7 per cent disease reduction. Fenazaquin (0 .1%) spray reduced the mite (Aceria cajani) population by 81.9 per cent followed by winter green oil 30 EC (2 %) with the population reduction of 72.3 per cent. Fenazaquin (0 .1%) spray also influenced to record the highest yield of 815 kg per ha as against 492 kg per ha in untreated plot and therefore, 0.1% Fenazaquin could be the best alternative for the management of SMD in pigeonpea under field conditions.

Multi-environment field testing to identify broad, stable resistance to sterility mosaic disease of pigeonpea

Sterility mosaic disease (SMD) caused by Pigeonpea sterility mosaic virus and vectored by the eriophyid mite is a serious disease of pigeonpea in almost all pigeonpea-growing areas. Managing the disease with chemicals such as acaricides is very difficult, non-eco-friendly and costly; hence, host plant resistance is the best strategy implemented to manage this disease. In this context, 28 pigeonpea genotypes identified as resistant from preliminary screening of 976 pigeonpea accessions were evaluated in field at eight different agro-ecological locations in India for the stability of their resistance against SMD during 2007/2008 and 2008/2009. Genotype plus genotype × environment (GGE) analysis partitioned main effects into genotype, environments and G × E interactions and showed significant effects (P < 0.001) for SMD percentage incidence. Environment variance had the greatest effect (76.68 %), indicating the maximum variation in the disease due to the environment. At Bangalore, Dholi and Rahuri locations, all genotypes were susceptible to SMD with mean disease incidence of 71.1, 50.4 and 32.6 % respectively. However, most of the genotypes were resistant at four locations, Akola, Badnapur, Patancheru, and Vamban, and moderately resistant at Coimbatore. The GGE biplot analysis explained about 67.26 % of total variation and identified four genotypes (ICPLs 20094, 20106, 20098, 20115) as the most stable and resistant to SMD. Three genotypes (ICPLs 20096, 20107, 20110) showed moderately stable performance against SMD. These genotypes should be included in pigeonpea breeding programs as additional sources of resistance to SMD.

Identification of Coupling and Repulsion Phase DNA Marker Associated With an Allele of a Gene Conferring Host Plant Resistance to Pigeonpea sterility mosaic virus (PPSMV) in Pigeonpea (Cajanus cajan L. Millsp.).

Pigeonpea Sterility Mosaic Disease (PSMD) is an important foliar disease caused by Pigeonpea sterility mosaic virus (PPSMV) which is transmitted by eriophyid mites (Aceria cajani Channabasavanna). In present study, a F2 mapping population comprising 325 individuals was developed by crossing PSMD susceptible genotype (Gullyal white) and PSMD resistant genotype (BSMR 736). We identified a set of 32 out of 300 short decamer random DNA markers that showed polymorphism between Gullyal white and BSMR 736 parents. Among them, eleven DNA markers showed polymorphism including coupling and repulsion phase type of polymorphism across the parents. Bulked Segregant Analysis (BSA), revealed that the DNA marker, IABTPPN7, produced a single coupling phase marker (IABTPPN7414) and a repulsion phase marker (IABTPPN7983) co-segregating with PSMD reaction. Screening of 325 F2 population using IABTPPN7 revealed that the repulsion phase marker, IABTPPN7983, was co-segregating with the PSMD responsive SV1 at a distance of 23.9 cM for Bidar PPSMV isolate. On the other hand, the coupling phase marker IABTPPN7414 did not show any linkage with PSMD resistance. Additionally, single marker analysis both IABTPPN7983 (P<0.0001) and IABTPPN 7414 (P<0.0001) recorded a significant association with the PSMD resistance and explained a phenotypic variance of 31 and 36% respectively in F2 population. The repulsion phase marker, IABTPPN7983, could be of use in Marker-Assisted Selection (MAS) in the PPSMV resistance breeding programmes of pigeonpea.

Evaluation of medium duration pigeonpea hybrid under rainfed situation

Field trials of 12 genotypes including nine hybrids and three checks, Maruti, Asha and Birsa Arhar-1 were conducted under rainfed conditions. Analysis of variance for all the ten characters for each environment and on pooled basis indicated highly significant variation over the seasons, except pod size which was significant at 5% level only. Highest pooled grain yield of 2259.5 kg/ha was recorded in Hybrid ICPH 2740, which was at par with ICPH 3933 (2131.8) and ICPH 2671 (2101.5 kg/ha) as compared to the best check, Birsa Arhar-1 (1689 kg/ha). ICPH 2740, ICPH 3933 and ICPH 2671 showed resistant reaction to wilt and sterility mosaic disease of pigeonpea. Hybrids ICPH 2740 and ICPH 2671 were identified as stable in respect of yield as well as infestation of disease and insect pest.

Detection of pigeonpea sterility mosaic virus, the causal agent of sterility mosaic disease of pigeonpea in viruliferous mite vector by DAS-ELISA and DIBA

The sterility mosaic virus in pigeonpea is transmitted by the eriophyid mite Aeria cajani. Serological diagnostic methods like DAS-ELISA and DIBA were developed to detect the presence of Pigeonpea Sterility Mosaic Virus (PPSMV) from their viruliferous vector using whole mite extract as an antigen. Both DAS-ELISA and DIBA were sensitive for virus detection in vector mites. Extract from 180 mites gave a strong positive reaction. A weak positive reaction was observed in a minimum of 10 viruliferous mites by DAS-ELISA. Whereas the virus was detected from the extract of a minimum of 5 mites by DIBA. This indicated that DIBA is more sensitive for virus detection in vector mites when compared to DAS-ELISA.

Broad‐based resistance to pigeonpea sterility mosaic disease in wild relatives of pigeonpea (Cajanus: Phaseoleae)

SummarySterility mosaic disease (SMD), an important biotic constraint on pigeonpea (Cajanus cajan) in the Indian subcontinent, is caused by Pigeonpea sterility mosaic virus (PPSMV) transmitted by the eriophyid mite, Aceria cajani. Distinct PPSMV isolates occur in different geographical regions and broad‐based resistance to all these isolates is scarce in cultivated pigeonpea germplasm. Wild relatives of pigeonpea, which are known to possess resistance to several pests and diseases, were evaluated for broad‐based SMD resistance. One hundred and fifteen wild Cajanus accessions from six species (C. albicans, C. platycarpus, C. cajanifolius, C. lineatus, C. scarabaeoides and C. sericeus) were evaluated against three PPSMV isolates prevailing in peninsular India. Evaluations were done under greenhouse conditions in endemic locations of each isolate through mite‐mediated virus inoculation. Fifteen accessions showed resistance to all three isolates: ICP 15614, 15615, 15626, 15684, 15688, 15700, 15701, 15725, 15734, 15736, 15737, 15740, 15924, 15925 and 15926. Most of the wild accessions did not support mite multiplication. The majority of the accessions resistant to PPSMV following inoculations with viruliferous mites were susceptible by graft inoculation, suggesting that vector resistance is conferring resistance to infection with PPSMV. The 15 accessions identified as being resistant to infection to all three virus isolates tested are cross compatible with pigeonpea by traditional breeding. They are therefore useful for exploitation in breeding programmes to increase both the level of SMD resistance and to diversify its genetic base in the cultivated pigeonpea gene pool.

A Novel Mite-Transmitted Virus with a Divided RNA Genome Closely Associated with Pigeonpea Sterility Mosaic Disease

ABSTRACT The agent of sterility mosaic, a disease that is a major constraint on pigeonpea (Cajanus cajan) production in the Indian subcontinent, is transmitted by the eriophyid mite, Aceria cajani. This agent has remained elusive for decades despite intensive efforts but we report the isolation of highly flexuous filamentous virus-like particles (VLPs) of 3 to 10 nm in width and of undefined lengths from sterility mosaic disease (SMD)-affected pigeonpea plants. Purified VLP preparations from virus-infected pigeonpea and Nicotiana benthamiana had a buoyant density in cesium chloride of 1.22 to 1.23 g cm(-3) and contained a major virus-specific protein species of approximately 32 kDa and 5 to 7 RNA species of approximately 6.8 to 1.1 kb. The sequence of some complementary DNA clones to RNA from purified VLP preparations had no significant matches in database searches. Two oligonucleotide primers derived from one such sequence, when used in reverse transcriptase-polymerase chain reaction assays, amplified a product of 321 bp specifically from SMD-affected pigeonpea plants. Purified VLP preparations were used to produce polyclonal antibodies that, in infected plants, detected the virus using enzyme-linked immuno-sorbent assay (ELISA) and the virus-specific 32-kDa protein in western immunoblotting (WIB). In such assays, the virus was detected consistently in all SMD-affected pigeonpea plant samples from several different locations in India, but not in samples from symptom-free pigeonpea plants from the same locations. In experimental studies, all pigeonpea plants inoculated with viruliferous A. cajani and those plants graft-inoculated with SMD-affected tissue were infected with the virus as assessed by ELISA and WIB, but not any uninfected pigeonpea plants. This virus, tentatively named Pigeonpea sterility mosaic virus (PPSMV), has some properties similar to virus species in the genera Tospovirus and Tenuivirus and with the eriophyid mite-transmitted High plains virus (HPV) but is distinct from these and from all other characterized viruses. The combination of novel properties shown by PPSMV and HPV suggest that they may constitute species in a new genus of plant viruses.

Assessment of variation in Aceria cajani using analysis of rDNA ITS regions and scanning electron microscopy: implications for the variability observed in host plant resistance to pigeonpea sterility mosaic disease

Summary Aceria cajani on pigeonpea (Cajanus cajan) is the vector of the agent of pigeonpea sterility mosaic disease (PSMD), a very damaging virus‐like disease in the Indian subcontinent. PCR was used to amplify A. cajani nuclear ribosomal DNA (rDNA) internal transcribed spacers (ITS) and associated rDNA genes. They were assessed for variation in this genome region by nucleotide sequencing and RFLP. A. cajani‐specific rDNA primers are described. Several A. cajani populations were collected from pigeonpea plants from various PSMD endemic locations in India, Nepal and Myanmar. No significant variation was identified in rDNA regions, or in morphological features. These results suggest strongly that A. cajani on pigeonpea across the Indian subcontinent constitutes one species and that no other Aceria species and probably no A. cajani biotypes that differ in vectoring ability are involved in the transmission of the agent of PSMD. The implications of these findings for the variability observed in PSMD‐resistant pigeonpea genotypes across various locations in India are discussed.

Characterization of a Virus from Pigeonpea with Affinities to Species in the Genus Aureusvirus, Family Tombusviridae.

In attempts to identify the causal agent of pigeonpea sterility mosaic disease (PSMD), which is transmitted by eriophyid mites, a virus was isolated with great difficulty from some PSMD-affected pigeonpea (Cajanus cajan) plants from different locations in India. Once isolated from pigeonpea, the virus was transmitted readily by mechanical inoculation to several herbaceous species, reaching very high concentrations in some species. The virus was transmitted experimentally through soil to herbaceous test plants but not to pigeonpea. When virus particles were purified and inoculated mechanically to healthy pigeonpea, the virus induced necrosis in inoculated leaves only and did not spread systemically. Therefore, the virus is not the causal agent of PSMD. The virus has isometric particles approximately 30 nm in diameter that sediment as a single component and had a buoyant density in CsCl and Cs2SO4 of 1.34 and 1.27 g·cc-1, respectively. Purified virus particle preparations contained a single major protein of approximately 44 kDa and three RNA species of approximately 4,300, 2,700, and 1,500 nucleotides. Only the largest RNA species was infective to plants; the two smaller species were encapsidated subgenomic species of the 3' end of the larger genomic RNA. The viral genome was sequenced and showed 93% homology to that of Pothos latent virus (PoLV), a recently described virus in the genus Aureusvirus, family Tombusviridae, and was indistinguishable from PoLV in gel double-diffusion serological tests. This virus, therefore, is regarded as a pigeonpea isolate of PoLV (PoLV-PP). In field studies in different locations in India, enzyme-linked immunosorbent assay and reverse-transcriptase polymerase chain reaction detected PoLV-PP in 10.7% of PSMD-affected and 8.1% of asymptomatic pigeonpea plants. The significance of these findings is discussed.

Studies on pigeon pea sterility mosaic disease

Studies on pigeon pea sterility mosaic disease

Studies on pigeon pea sterility mosaic disease

PSMV-affected pigeon pea generally had a lower level of calcium, the decrease being conspicuous in older leaves than healthy counterparts. Potassium level decreased in diseased leaves at all ages, petiole, stem and root than comparable healthy tissues. Sodium level was significantly lower in fourth and fifth leaves in diseased plant. Diseased leaves had a lower level of manganese at all ages than healthy counterparts.