Guava and litchi pest’s mitochondrial genome decoded

Shillong, April 27, 2019 (MMP): For the first time, researchers from ICAR Research Complex for NEH Umiam have mapped the mitochondrial genome of a beetle1, known as guava trunk borer, the beetle thrives on the guava and litchi trees in the North-eastern region of India. To address this issue, an international research team, which included scientists from the ICAR Research Complex for NEH Region, the Punjab Agricultural University in Ludhiana and the ICAR-Indian Agricultural Research Institute (IARI) in New Delhi, all in India, has sequenced the mitochondrial genome of the beetle collected from the state of Meghalaya. Decoding its mitochondrial genes will be useful for DNA bar-coding, a method of identifying species of different organisms based on a short and standardised fragment of genomic DNA. Aristobiareticulator (Coleoptera: Cerambycidae) is also known as guava trunk borer, litchi stem borer or litchi longhorn beetle.  It is as an important pest of guava and now litchi in India. This pest has been distributed in many countries (Nepal, India, China, and Vietnam). In India, it is mainly restricted to North-eastern region of the country.  To address this issue and to generate the genomic resources especially for the coleopteran family, Cerambycidae, a complete mitochondrial genome was successfully sequenced and characterized. Dr. G. T. Behere Principal Scientist (Agril Entomology) and Principal Investigator of the Project added that the size of complete mitochondrial genome of A.reticulator was determined to be 15838 bp long and circular in nature and has total of 13 protein coding genes (PCGs), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes and one control region (A+T-rich region). 

           The gene arrangement and orientations of assembled mitogenome were identical to the published mitogenomes of coleopteran insect species. This is the first complete mitogenome of the coleopteran family cerambycidae from India.  The beetles feed on the tree bark, while their larvae tunnel inside the stem. A recent survey, conducted in Arunachal Pradesh, has shown that it wreaks havoc on the local litchi trees.  Despite its economic importance as a pest, there is no molecular data available for this beetle. The researchers, led by Ganesh Behere, found that the beetle’s mitochondrial genome, long and circular in nature, contains 15,838 base pairs. It has 13 genes that encode specific proteins and 24 RNA-related genes involved in protein synthesis. The arrangement and orientations of the genes in the beetle’s mitochondria are identical to other insect species that belong to the order Coleoptera, the largest order of insects, consisting mostly of the beetles and weevils. The knowledge of the complete mitochondrial genome will allow in designing a better management strategy for controlling the insect pest in India.

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