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Dept. of Plant Molecular Biology and Biotechnology,CPCA, S. D. Agricultural University.

Prepared by: Darshan T. DharajiyaPh.D. (Plant Molecular Biology and Biotechnology)

Pulses as universal crops Viruses as a major constrain in pulse production Yellow Mosaic Disease (YMD) Mungbean Yellow Mosaic Virus (MYMV) Symptomology of YMD Losses due to YMD Transmission of YMV Epidemiology Disease Management Biochemical changes due to YMD Defence mechanism in plant by Salicylic Acid (SA) Natural defence mechanism

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Pulses are the universal crops rated as one among the important crops in the world. Because of their possession of the biological nitrogen fixing mechanism, they inherited the in situ high protein contribution.

Globally, 60 million tonnes of pulses are produced annually from 70 million hectares (Anonymous, 2010).

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The contribution of developing countries like India, China, Brazil, Turkey and Mexico accounts for nearly two third productions.

India is the largest producer with 33 per cent of global area contributing 22 per cent of the world's production.

In India, pulses are cultivated to an extent of 22.37 million hectares with an average production of 14.66 million tonnes with an average productivity 655 kg per hectare in India during the year of 2008-09 (Anonymous, 2010).

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Five most important pulse crops depending upon there contribution in national production viz., chickpea (39%) pigeonpea (21%) mungbean (11%) urdbean (10%) lentil (7%)

They account for over 80 per cent of the total pulses production in the country.

Over 60 per cent of pulses produced in India are grown during the rabi season.

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Particulars Area Per cent Production Per cent Productivity

Chickpea 73.7 38.71 58.9 48.28 799.19

Pegionpea 36.3 19.07 27.6 22.62 760.33

Mungbean 34.4 18.07 14 11.48 406.98

Uradbean 31 16.28 14 11.48 451.61

Lentil 15 7.88 9.5 7.79 633.33

Total 190.4 100.00 124 101.64 651.2

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Area production and productivity of major pulses in India (Area: lakh ha, Production: Lakh tonnes, Productivity: kg/ha)

http://agropedia.iitk.ac.in/content/area-production-and-productivity-major-pulses

(Anonymous, 2011)

Area production and productivity of major pulses in India

Crop States to be coveredChickpea Madhya Pradesh (32.97%), Maharashtra (18.36%), Rajasthan (16.70%),

Andhra Pradesh (8.55%), Karnataka (8.21%), Uttar Pradesh (6.85%) and Gujarat (2.92 %)

Pigeonpea Maharashtra (32.37%), Karnataka (18.76%), Andhra Pradesh (12.75%), Uttar Pradesh (10.14%), Madhya Pradesh (9.64%) and Gujarat (6.69%)

Mungbean Rajasthan (30.81%), Maharashtra (19.51%), Karnataka (15.35%), Andhra Pradesh (12.79%), Orissa (7.41%), Tamil Nadu (4.97 %) and Uttar Pradesh (2.09%)

Urdbean Maharashtra (18.55%), Andhra Pradesh (16.23%), Madhya Pradesh (18.55%), Uttar Pradesh (12.61%), Tamil Nadu (11.00), Rajasthan (4.68), Orissa (4.84%) and Karnataka (4.06)

Lentil Madhya Pradesh (40.53%), Uttar Pradesh (37.60%), Bihar (10.80%) and West Bengal (4.00%)

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Important pulse crops in major States on area under the pulses

http://agropedia.iitk.ac.in/content/area-production-and-productivity-major-pulses

(Anonymous, 2011)

Crop States to be coveredChickpea Madhya Pradesh (29.37%), Maharashtra (20.03%), Andhra Pradesh

(15.48%), Rajasthan (9.73%), Karnataka (9.63%), Uttar Pradesh (6.42%) & Gujarat (3.57 %)

Pigeonpea Maharashtra (39.24%), Karnataka (17.57%), Andhra Pradesh (10.94%), Uttar Pradesh (11.85%), Gujarat (10.65%) and Madhya Pradesh (7.86%)

Mungbean Rajasthan (34.67%), Maharashtra (30.92%), Andhra Pradesh (18.08%), Karnataka (9.00%), Orissa (5.17%), Tamil Nadu (4.58%) and Uttar Pradesh (3.33%)

Urdbean Maharashtra(23.36%) AP(18.50%), UP(12.29%), MP(11.86%), Tamil Nadu (8.64%), Karnataka (4.57%), Rajasthan (4.29%) and Orissa (3.00%)

Lentil Uttar Pradesh (45.79%), Madhya Pradesh (30.21%), Bihar (12.00%) and West Bengal (4.21%)

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Important pulse crops in major States on production of the pulses

http://agropedia.iitk.ac.in/content/area-production-and-productivity-major-pulses

(Anonymous, 2011)

9(Annonymous, 2008)

Most emerging infectious diseases of plants are caused by viruses (Anderson et al., 2004).

One of the major constrains in pulse production are pathogens and viruses are among the most important groups of plant pathogens affecting pulse production worldwide.

Plant viral diseases cause serious economic losses in many major crops by reducing seed yield and quality (Kang et al., 2005).

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Among the various diseases, the mungbean yellow mosaic virus (MYMV) disease was given special attention because of severity and ability to cause yield loss up to 85 per cent (AVRDC, 1998).

Host resistance to the disease and/or the vector has therefore been considered as the only solution to control this important disease (Kang et al., 2005).

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The host range of the virus was reported to be largely confined to the plants belonging to the family Leguminaceae.

The legumes like black gram, mungbean, moth bean and pigeon pea from the hosts for the MYMV.

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The yellow mosaic disease (YMD) of mungbean was first observed in India in 1955, at the experimental farm of the Indian Agricultural Research Institute, New Delhi. (Nariani, 1960)

Yellow Mosaic Disease (YMD) is reported to be the most destructive viral disease among the various viral diseases, caused by Yellow Mosaic Virus. It causes severe yield reduction in all mungbean growing countries in Asia including India (Biswass et al., 2008).

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MYMV have been placed in two virus species, Mungbean yellow mosaic India virus (MYMIV) and Mungbean yellow mosaic virus (MYMV) on the basis of nucleotide sequence identity (Fauquet et al., 2003).

Mungbean Yellow Mosaic India Virus (MYMIV) (Mandal et al., 1997) and Mungbean Yellow Mosaic Virus (MYMV) (Morinaga et al., 1990) were suggested to be associated in the etiology of Yellow Mosaic Diseases (YMD) of legumes in India and South Asia.

MYMV and MYMIV occur across the Indian subcontinent.

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Four species viz., Mungbean yellow mosaic virus (MYMV) Mungbean yellow mosaic India virus (MYMIV) Dolichos yellow mosaic virus (DYMV) Horsegram yellow mosaic virus (HYMV) are known to cause yellow mosaic disease in

different leguminous species.

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MYMV affects the majority of legume crops including mungbean (V. radiata (L.)) black gram (Vigna mungo (L.) Hepper) pigeonpea (Cajanus cajan (L.) mill sp.) soybean (Glycine max (L.) Merr.) mothbean (Vigna aconitifolia (Jacq.) common bean (Phaseolus vulgaris (L.) (Javaria et al., 2007).

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MYMV belongs to the genera begomovirus of the family Geminiviridae (Bos, 1999) (Fauquet et al., 2003).

The largest genus, Begomovirus, currently contains 132 species (Fauquet and Stanley, 2005).

The virus has geminate particle morphology (20 x 30 nm capsid) and the coat protein encapsulates spherical, single stranded DNA genome of approximately 2.8 Kb (Hull, 2004).

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The genus begomovirus includes geminivirus species with bipartite genomes (DNA-A and DNA-B) or monopartite genomes that were transmitted in a circulative persistent manner by white fly Bemisia tabaci (Nariani, 1960).

The opposing transcription units of begomovirus DNA-A and-B molecules are

separated by an intergenic region (IR) that generally shares a highly conserved region of approximately 200 nt, named the common

region (CR).

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DNA-A typically has six open reading frames (ORFs): AV1/V1 (coat protein, CP) and AV2/V2 (AV2/V2 protein) on the virion-sense strand, and AC1/C1 (replication initiation protein, Rep), AC2/C2 (transcriptional activator, TrAP), AC3/C3 (replication enhancer, REn) and AC4/C4 (AC4/C4 protein) on the complementary-sense strand.

DNA-B has two ORFs encoding movement proteins: BV1 (nuclear shuttle protein, NSP) on the virus-sense strand and BC1 (movement protein, MP) on the complementary-sense strand (Rojas et al., 2005 & Seal et al., 2006).

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Genome and transcriptome of MYMV. The MYMV bipartite genome comprises two components, DNA-A and DNA-B (variant KA22) (gray circles), of 2,728 and 2,660 nt,

respectively, which share a CR containing an invariant nonanucleotide (boxed) with a nick site (indicated between t and a; the numbering starts from the latter nucleotide).

Shivaprasad P V et al. J. Virol. 2005;79:8149-8163

YMV causes irregular green and yellow patches in older leaves and complete yellowing of younger leaves.

Affected plants produce fewer flowers and pods, pods often develop mottling, remain small and contain fewer and smaller seeds thus affecting yields qualitatively and quantitatively.

Infected leaves also show necrotic symptoms. Diseased plants are stunted and mature late. Reduction in number of pods/plant, seeds/pod and seed

weight are the main contributing factors for yield reduction (Nene, 1973; Dhingra and Chenulu, 1985).

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Irregular green and yellow patches in older leaves

complete yellowing of younger leaves

Depending on the severity of the disease, the yield penalty may reach up to cent percent (Basak et al., 2004).

However, based on the incidence of MYMV in mungbean, urdbean and soybean, an annual loss of over US$ 300 million is estimated in these crops (Varma et al., 1992).

Among the various diseases, Yellow Mosaic Disease (YMD) is reported to be the most destructive viral disease caused by Yellow Mosaic Virus and it leads to severe yield reduction not only in India, but also in Pakistan, Bangladesh and contiguous areas of South East Asia (Biswass et al., 2008 & John et al., 2008).

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It can cause up to 100 per cent yield loss if infection occurs three weeks after planting, loss will be small if infection occurs after eight weeks from the day of planting.

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Quaiser Ahmed (1991) reported a yield loss of 83.9 per cent and a maximum growth reduction of 62.94 per cent in Vigna radiata cv. Pusa baisakhi due to mungbean yellow mosaic gemini virus infection and he also concluded that early crop infection reduced yield more than late infection.

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Aftab et al. (1993) reported MYMV infection on Vigna ungiliculata sub sp. sesquipedalis at Islamabad, Pakistan.

The disease spread rapidly with increase in whitefly population.

Plant height, number of pods, seeds and yield/plant were reduced by 10.3, 50.5, 44.7 and 49.2 per cent, respectively.

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Chlorotic, irregular, yellow patches on the leaves of the susceptible plants are characteristic symptoms of virus infection; which probably and as a consequence decreases photosynthetic efficiency yield of the crop is affected.

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Geminiviruses are known to infect phloem tissues, although they can also invade mesophyl cells.

The exact invasion process of geminiviruses in plants is not fully understood.

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Mechanical transmission: Attempts were made by Nariani (1960) to

transmit the disease by sap inoculation by rubbing freshly extracted sap of mosaic affected leaves on the healthy young seedlings of mung.

However, the disease could not be transmitted in this manner.

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Graft transmission: Nariani (1960) and Ahmed and Harwood

(1973) reported that transmission of MYMV was successful by grafting.

Chenulu and Varma (1988) reported that in grafted plants symptoms appear in the young auxillary shoots below the scion in 12-15 days of grafting.

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Insect transmission: Nariani (1960) first to report the occurrence

of mung yellow mosaic and its transmission by the whitefly Bemisia tabaci (Genn.) predominantly and it has been reported to be the vector of similar diseases on Phaseolus lunatus L. by Capoor and Varma (1948) and on Dolichos lablab by Capoor and Varma (1950a).

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Seed transmission: Bock (1982) reported that none of the gemini

viruses appears to be seed transmitted. Nariani (1960) found that mungbean seed

does not transmit mungbean yellow mosaic virus.

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Murugesan and Chelliah (1977) reported a yellow mosaic on greengram sown during March to May months.

The increased disease incidence might be attributed to the higher temperatures prevalent during these months, which was favourable for the vector, Bemisia tabaci to develop and multiply.

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YMD incidence was more during summer (February to March).

The population of MYMV vector whitefly, Bemisia tabaci (Gennadius) thrives best under hot and humid condition that is another reason for higher incidence of disease during summer (Malathi and John, 2008).

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The spread of virus was gradual, cumulative and was in direction of prevalent wind thus depending on vector population built-up.

In northern India, with the onset of monsoon rain (June to July) population of vector increased and the rate of spread of virus were also increased whereas before the monsoon rain the population of B. tabaci was non-viruliferous.

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Singh and Gurha (1994) studied the influence of cropping seasons on incidence of yellow mosaic in mungbean genotypes.

All the genotypes showed a higher disease incidence during summer compared to spring and rainy season crops.

This is attributed to unfavourable conditions for multiplication of the vector Bemisia tabaci in spring and rainy seasons.

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Cultural control: Grow seven rows of sorghum as border crop.

Raghupathi and Sabitha (1994). Ravindrababu (1987) reported that maize, sorghum

and pearl millet barrier crops, sprayed with endosulfan were effective in reducing the incidence of mungbean mosaic as compared to barrier crops, which were not sprayed.

Yellow sticky traps attracts adult white flies. Uthamasamy (1989)

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Plant products and derivatives: Chandrasekharan and Balasubramanian (2002) evaluated the

efficacy of botanicals and insecticides against sucking pests, viz., aphid, Aphis craccivora Koch. and whitefly, Bemisia tabaci Genn. on greengram.

They reported that among the treatments, acephate 75 SP @ 0.075 per cent and TNAU neem oil (C) 60 EC at 3.0 per cent were found significantly superior by recording higher percentage of reduction in aphid population and yellow mosaic virus (YMV) incidence due to whitefly and also with grain yield recording 8.5 and 7.4 q/ha, respectively.

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Chemical control: Borah (1995) reported that the foliar

application of cypermethrin (0.01, 0.015%), deltamethrin (0.0028, 0.0042%) and dimethoate (0.03, 0.04 – 5%) were effective in reducing whitefly incidence in green gram.

Treat seeds with Imidacloprid 70 WS @ 5ml/kg to control vector.

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Rogue out MYMV infected plants early in the season to eliminate the source of inoculum.

Grow resistant varieties to yellow mosaic. ML 1, ML 5, ML 6, Meha, Vamban 2 as a resistant

variety in Mungbean. Pant U 19, Pant U26 and Pant U 30 as a resistant

varieties in Urdbean.

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Virus infected leaves had significantly higher moisture percentage and less chlorophyll and sugar contents when compared with the healthy leaves.

Seeds of infected plants contained significantly lower percentages of chlorophyll, proteins, sugars, phenols, free amino acids and oils as compared with the seeds of healthy soybean plants. (Kaur et. al. 1991).

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Total chlorophyll, chlorophyll a, chlorophyll b content and carbohydrate content decreased in virus infected mungbean varieties.

Total nitrogen and total protein content increased and total phosphorus content was found to be very high in virus infected plant. (Sinha et. al., 2010)

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Kundu et.al., (2011)

Twenty-nine proteins identified by MALDI-TOF/TOF, predicted to be involved in stress responses, metabolism, photosynthesis, transport and signal transduction, showed increased abundance upon SA treatment.

Susceptible plants showed characteristic yellow mosaic symptoms upon MYMIV infection.

A concentration dependent decrease in physiological symptoms associated with MYMIV was observed upon exogenous SA treatment prior to viral inoculation; and no visible symptom was observed at 100 μM SA.

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SA treatment stimulated SOD and GPX activity and inhibited CAT activity thus preventing ROS mediated damage.

Significant increase in chlorophyll, protein, carbohydrate, phenolic content and H2O2were observed. Involvement of calmodulin for transmission of defense signal by SA is suggested.

A metabolic reprogramming leading to enhanced synthesis of proteins involved in primary and secondary metabolisms is necessary for SA mediated resistance to MYMIV.

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The resistant variety displayed synthesis but rapid degradation of the early viral RNAs; the degradation in the susceptible variety was delayed resulting in accumulation of those transcripts later in infection.

Accumulation of the late viral transcripts and DNA replication were detectable only in the susceptible variety.

This indicates that rapid degradation of the early viral transcripts, possibly through siRNA mechanism, is one of the probable mechanisms of natural resistance against geminivirus.

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http://agritech.tnau.ac.in/crop_protection/crop_prot_crop%20diseases_pulses_greengram.html

http://www.growmorepulses.com/upload/images/india_pulses_state_big.gif G. Kaur, C.K. Gill, H.S. Rataul, R.K. Raheja (1991). Biochemical Changes in Soybean (Glycine

max L.) Cultivars Infected with Yellow Mosaic Virus. Biochemie und Physiologie der Pflanzen, 187 (5): 357–371.

A. Sinha and M. Srivastava (2010). Biochemical Changes in Mungbean Plants Infected by Mungbean yellow mosaic virus. International Journal of Virology, 6: 150-157.

Subrata Kundu, Dipjyoti Chakrabortya, Amita Pala (2011). Proteomic analysis of salicylic acid induced resistance to Mungbean Yellow Mosaic India Virus in Vigna mungo. Journal Of Proteomics. 74: 337–349.

Rajiv Kumar Yadav, Rakesh Kumar Shukla, Debasis Chattopadhyay (2009). Soybean cultivar resistant to Mungbean Yellow Mosaic India Virus infection induces viral RNA degradation earlier than the susceptible cultivar. Virus Research, 144 (2): 89-95.

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