A. Abdelkhalek - Plant Protection and Bimolecular Diagnosis Department, ALCRI, City of Scientific Research and Technological Applications, ۲۱۹۳۴, Alexandria, Egypt.
N. Sanan-Mishra - Plant RNAi Biology Group, International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India.

Plant microRNAs (miRNAs) play important roles in plant development and responses to biotic and abiotic stress. Recently, there is clear evidence that miRNAs are involved in host-virus interactions. By using stem-loop RT-PCR, an expression levels change of thirteen miRNA belonging to six miRNA families targeting leaf development and morphogenesis were analyzed upon Tobacco Mosaic Virus (TMV)-tomato infection. Compared to mock plants, significant changes in relative expression levels of nine miRNAs were observed. The miR۳۱۹c-۵p showed the highest statistically significant increase in accumulation at ۱۵ days post-inoculation. At all time points tested, miR۱۵۹, miR۱۶۴a-۳p, miR۱۶۴a-۵p, miR۱۶۶c-۵p and miR۳۱۹c-۵p were up-regulated while miR۱۶۰, miR۳۱۹a, miR۳۱۹b, miR۳۱۹c-۳p were down-regulated in most cases. Our data could provide new insights into the role of miRNAs in tomato-TMV interaction and in developing efficient strategies for improving tomato resistance against viral infection.

Host-virus interaction, Stem-loop, RT-PCR, TMV, Viral infection.