Insects are the dominant animals in the world, with more than one million described species. Insects, not only produce direct damage to plants but also acts as a vector for various pathogens. In recent years, next-generation sequencing (NGS) techniques have provided fascinating opportunities to understand the basic biology, biochemistry, and molecular biology of these intimate and intriguing relationships. The decrease in sequencing costs and extensive sequencing services from NGS providers has brought many scientists to be involved in genome sequencing of insects and their associated entomopathogens. By using high-throughput genomic technologies, scientists can elucidate the virulence, host adaptation and gene function of the particular entomopathogen including virus, fungi, bacteria and nematode.
In recent years, high-throughput next-generation sequencing (NGS) techniques have provided fascinating opportunities to understand the biology of non-model organisms, especially insect species. The decrease in sequencing costs and extensive sequencing services from NGS providers has brought many entomologists to be involved in genome sequencing. However, poor planning can lead to extremely fragmented genome assemblies which prevents high quality gene annotation and other desired analyses. Insect genomes can be problematic to assemble, due to combinations of high polymorphism, inability to breed for genome homozygosity, and small physical sizes limiting the quantity of DNA able to be isolated from a single individual. Given to the rapid development of host resistance to multiple classes of insecticides, it is indispensable to study the comprehensive genomic information of insects. Recent advances in sequencing technology and assembly strategies can able to fetch breakthroughs in deciphering the genetic information of insects. Here, we present the cost effective high throughput genome sequencing and assembly strategies for insect species in respects to taxonomy, evolutionary history, immune response, drug development, insect host-virus interactions and pest management etc.
Leptotrombidium pallidum is the major vector mites for Orientia tsutsugamushi, the causative agent of scrub typhus. To understand the molecular mechanism of L. pallidum, we sequenced the whole genome using Illumina sequencing technology. Totally four genomic libraries with different insert sizes ranging from 280 bp to 8 kb were used to generate 45.1 Gb of genome in the combination of paired-end and mate-pairs sequencing reads. Quality filtering and correction of paired-end reads for very small and/or bad-quality sequences yielded 26.9 Gb of high-quality sequences, which are used to estimate the genome size as 175 Mbusing kmer methods and assembled into a 193.7 Mb genomic sequence scaffolds with N50 length of 92,945 bp. Furthermore, 94% of CEGMA completeness score were obtained from genome scaffold assembly. To facilitate gene annotation, we used a combination of de novo and homology based tools to predict gene models in the chigger mite genome. A combination of evidence-based and de novo approaches predicted 15,842 high-confidence protein-coding genes with an average transcript length of 1,511 bp and 2.4 exons per gene which corresponds to about 12.4% total gene length. Bacterial endosymbiosis are very common in mite species and can range from mutualistic to pathogenic associations. Henceforth, the endosymbionts in L. pallidum were predicted using the NCBI microbial draft genomes and mitochondrial genome. Besides, this L. pallidum draft genome can be used as a significant reference for comparative genomic studies across mite species.
Grain yield, one of the most important agronomic traits, is greatly affected by architecture in rice. Here, we show that an OsPrMC3, a rice PrMC3 orthologue with a lipase or esterase domain, involves in yielding by tillering. Phenotypic analysis of T-DNA insertion mutant revealed that it has high number of tillers than wild type although height and leaf width are shorter and narrower than wild type. Size and branch number of panicle were greatly reduced in the mutant, which resulted in significant decrease of seed number per panicle and dry weight of the seeds. OsPrMC3 is highly expressed in the leaf during the early stage of development. However, it is mainly expressed in mature seed and root after flowering although its expression is detected in all of the tissues. Our result indicates that OsPrMC3 involves in leaf growth and tillering during vegetative growth and also seed development after flowering, suggesting its crucial regulatory role in yielding
and distribution of seed storage proteins are responsible for the quality of soybean and seed development. Among storage proteins, lipoxygenase isoforms (Mw. ~97 kDa) play a major role in the distinct bean flavor during storage. In this study, we compared three soybean elite cultivars viz., JIMPUM, JINPUM2 and TANMI2 (lipoxygenase null mutants, originated from Japan) along with WILLIAMS 82 (control plant, USA) to determine the seed storage proteins by proteomic approach. Phenotype of the mature seeds showed the variation in seed coat, color and appearance. Total seed proteins of the above cultivars were subjected to two dimensional gel electrophoresis (2-DE). The resulted protein profiling showed the intensity of the different quantitative spots varied among the four cultivars. We are now investigating by using other proteomic tool and the resulted difference in proteins may helpful in quality improvement or the functional roles in the seed development.