Analysis of the control region of the mitochondrial genome of the Indian brown planthopper (BPH, Nilaparvata lugens) populations
Student name: Ms Rashi Anand
Guide: Dr Ramakrishnan Sitaraman
Year of completion: 2017
Host Organisation: ICGEB, New Delhi
Supervisor (Host Organisation): Dr Suresh Nair
Abstract: The brown planthopper (BPH; Nilaparvata lugens) is the most destructive pest of paddy
in India. BPH is capable of traversing large distances and therefore, widely distributed
and cause massive crop loss. In order to devise effective control mechanisms, it is
necessary to understand the variability and identity of the insect population prevalent in
an area. In this study, we show that the repeats present in the control region (CR) of the
mitogenome of the BPH are capable of broadly differentiating the populations of BPH.
The CR of 5 individuals each, from 5 different BPH populations (Delhi, Punjab,
Hyderabad, Warangal and Nalgonda) from India, were PCR amplified, using two
different primer pairs, as two overlapping fragments (~800 bp and ~1500 bp). These
fragments were cloned and sequenced. Using bioinformatics tools, the complete contig of
the CR was constructed and the iterations of a 21-bp repeat motif in the CR was evaluated
in each of BPH individuals screened. Frequency and distribution of nucleotides at specific
regions of the CR were also evaluated. Comparison of the CR sequences of the Indian
BPH individuals with that of the Chinese population revealed differences in the number
of iterations of the 21-bp repeat motif and nucleotide variations at other regions. The
number of iterations of the 21-bp repeat was by far more in the Chinese population than
all CR reported in this study. Phylogenetic analysis placed all the individuals representing
the South Indian populations under one clade. This study has identified a potentially
useful genetic marker capable of differentiating BPH populations. However, this needs to
be confirmed using a larger sampling. Successful development of such markers, capable
of rapidly identifying different populations of BPH, will be invaluable for developing
Integrated Pest Management (IPM) strategies for the effective management of such an
economically important pest of rice.
Keywords: Mitogenome, control region, biotypes, polymorphism, phylogeny.
