Journal of Environmental Biology

Role of leaf morphology in defense against sterility mosaic disease

of pigeonpea

L. Manjunatha^1,3*, H.K. Ramappa²,? and K.T. Rangaswamy³

¹Division of Crop Protection, Indian Institute of Pulses research, Kanpur-208 024, India

²AICRP (Pigeonpea), ZARS, UAS, GKVK, Bangalore-560 065, India

³Department of Plant Pathology, University of Agricultural Sciences, Bangalore-560 065, India

*Corresponding Author E-mail: manjupath@gmail.com

Key words

Emaravirus

Leaf morphology

Pigeonpea

Sterility mosaic virus

Publication Data

Paper received : 30.10.2016

Revised received : 12.06.2017

Re-revised received : 12.09.2017

Accepted : 27.09.2017

Abstract

Aim: Sterility mosaic disease is an emerging viral disease of pigeonpea, caused by Pigeonpea sterility mosaic virus, belongs to the newly established genus Emaravirus and transmitted by eriophyid mite-Aceria cajani Channa Basavanna causing >90 per cent yield loss in India. Therefore, the host range of virus and leaf characters were studied to identify the host preference and mechanism of resistance existing in pigeonpea cultivars against mite vector to develop stable resistant cultivars against sterility mosaic virus of pigeonpea.

Methodology: A study was conducted on host range through sap inoculation of different plant species and leaf morphological study. Previously identified sterility mosaic virus resistant and moderately resistant and susceptible genotypes were used for leaf characters study. The leaf cross and free-hand sectioning technique was followed using double-sided razor blade for leaf characters study. The measurements were taken after observing sections in stereo binocular microscope.

Results: Among the host plants tested, N. benthamiana was identified as test plant for identification of Pigeonpea sterility mosaic virus. Host preference for Pigeonpea sterility mosaic virus through sap inoculation revealed that Pigeonpea sterility mosaic virus-B isolate had limited host range and was able to infect only to Cajanus cajan[ICP 8863(Maruthi)], Phaseolus vulgaris and N. benthamiana and were confirmed by DAC-ELISA. Morphological traits such as thickness of cuticle, epidermis, number and length of leaf hairs of resistant cultivars (ICP-7035 and HY 3C) revealed significant difference compared to susceptible cultivars ICP-2376, ICP-8863 and TTB-7. ??? 

Interpretation: Host range study of sterility mosaic disease confirmed that Pigeonpea sterility mosaic virus had narrow host preference and this would help in formulating agronomic system in diseased localities and utilizing as a component in the IDM. In resistant cultivars higher thickness of cuticle, epidermis, more number and length of leaf hairs are possibly involved in vector mediated resistance. These results would help in development of stable and broad based resistance against sterility mosaic disease of pigeonpea.

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