Rahman, S. M. M. | Search bioRxiv

bioRxiv2024

Isolation, Characterization, and Identification of Nitrogen Fixing Bacteria from Rhizosphere of Sonneratia apetala Collected from Sundarbans

Nitrogen is a crucial element for plant growth, driving vibrant greenery, photosynthesis, and overall vitality. This research focused on isolating, characterizing, and identifying nitrogen-fixing bacteria from the rhizosphere of Sonneratia apetala in the Sundarbans, Khulna, Bangladesh, with the goal of assessing their potential as biofertilizers. Despite the Sundarbans rich microbial diversity, less than 5-10% of species have been identified due to challenges in culturing, which has limited exploration of their applications. In this study, nitrogen-fixing bacteria were isolated using nitrogen-free media, including yeast extract mannitol agar(YEMA) and Burks media, followed by an ammonification test to select ammonia-producing bacteria. This process yielded ten nitrogen-fixing bacterial isolates capable of producing indole-3-acetic acid (IAA). Various biochemical tests, including oxidase, catalase, methyl red, indole, urease, citrate, triple sugar iron, and starch hydrolysis, were conducted. The isolates, designated AK1 to AK10, were identified as Rossellomorea sp., Clostridium sp., Achromobacter sp., Pseudomonas sp., Gluconacetobacter sp., Scytonema sp., Pseudomonas sp., Nesterenkonia sp., Gluconacetobacter sp., and Bacillus sp., respectively. Additionally, isolates AK1, AK3, AK4, and AK10 were confirmed through 16S rRNA sequencing. A pot test further revealed that isolate AK-1 significantly stimulated the growth and development of maize seedlings. Future studies are needed to examine the impact of these bacterial isolates on crop yield and seed quality, to better determine their suitability as biofertilizers.

microbiology↗

bioRxiv2019

Whole genome sequencing of 358 brown planthoppers uncovers the landscape of their migration and dispersal worldwide

The brown planthopper (BPH), Nilaparvata lugens, is a serious migratory rice pest, which is distributed in the broad area of the tropical and temperate Asian-Pacific region. However, we know little about key aspects regarding its evolution such as how they diverged and dispersed worldwide. By resequencing and analyzing 358 BPH genomes from 92 populations across the world, we uncover the genetic relationships among their worldwide populations and the history of their global dispersal. We recovered five genetic groups representing the major population structures. Of these, Australian BPHs were shown large genetic divergence with Asian BPHs; two distinct groups have formed in South and Southeast/East Asia that show strong genetic admixture in the southwest border regions of China and west Thailand with Myanmar; two local populations in Bangladesh and Fujian province of China, respectively, unexpectedly separated with surrounding populations. We also find the genetic similarity and closely phylogenetic relationships between majority of East Asian BPHs and Indo-china peninsula BPHs, indicating that Southeast Asia mainland is the major insect sources and overwintering sites for East Asia. Our study provides important molecular evidence to address BPH evolution and other key aspects of its biology such as insecticides resistance and rice varieties virulence.

evolutionary biology↗