Conference
| Title | ENHANCING OXIDATIVE STRESS TOLERANCE AND LONGEVITY OF THE ENTOMOPATHOGENIC NEMATODE HETERORHABDITIS BACTERIOPHORA DAUER JUVENILES THROUGH GENETIC SELECTION Posted by Nanette Hope Sumaya |
| Authors | Sumaya, Nanette Hope; V. Doerfler; M. Barg; B. Vandenbossche; O. Strauch; C. Molina; R-U., Ehlers |
| Publication date | 2018/12/1 |
| Conference | IN JOURNAL OF NEMATOLOGY; 57th Annual Meeing of the Society of Nematologists |
| Volume | 50 |
| Issue | 4 |
| Pages | 658-658 |
| Publisher | SOC NEMATOLOGISTS: IN JOURNAL OF NEMATOLOGY |
| Abstract | The entomopathogenic nematodeâÃÂÃÂbacterium complex Heterorhabditis bacteriophora Photorhabdus luminescens is one of the most widely used biological control agents against several insect pests. The dauer juveniles (DJs) are third stage non-feeding and infective juveniles, which carry the symbiotic bacteria, survive in the soil to search for and penetrate insect hosts. For their industrial production, DJs are produced in large quantities (up to 40 m 3 ) in e-nema GmbH (Schwentinental, Germany). Subsequently, DJs are stored, formulated, transported and applied in the field. However, from production to application, DJs encounter environmental stresses (desiccation, hypoxia, UV radiation, heat, and oxidative stress) in each stage that influences longevity before they can actively kill the insect pests. Understanding therefore the genetic component of the stress responses in H. bacteriophora and improving DJ longevity are important research tasks. In this study, we combined approaches like classical breeding and next-generation genomics to acquire knowledge about and improve DJ oxidative stress tolerance and longevity. We first screen the oxidative stress tolerance in a wide collection of H. bacteriophora strains and inbred lines from different geographical locations under with and without oxidative stress inductions. We determined a high variability among strains of this species and a high heritability for oxidative stress (h 2 > 0.9). Oxidative stress was also found to have significant positive correlation with DJ longevity and persistence. Thus, oxidative stress can be used as a predictor for DJ longevity and persistence, permitting a selection process within a shorter testing period. In order to enhance tolerance to oxidative stress, longevity and persistence, several genetic crosses, EMS-mutants and homozygous inbred lines were generated. These genetic crosses, EMS-mutants and homozygous inbred lines were observed to have a higher tolerance to oxidative stress, extended longevity in water and higher infectivity against Tenebrio molitor compared to their respective parental (AU1 and HU2), donor (IL3) and commercial (EN01) lines. Furthermore, the oxidative stress-responsive transcriptome of two contrasting lines was analysed using Massive Amplification of cDNA Ends (MACE) and candidate genes were screened for polymorphisms. More than 500 SNPs have been detected between a high- and a low-surviving inbred line. PCR-based KASP markers were derived from relevant transcripts and were tested in natural H. bacteriophora materials. Significant correlation between genotype and phenotype was determined for a subset of KASP markers. This basic research sets the basis for marker assisted selection and further breeding activities to prolong shelf-life of the nematodes. |
| Index terms / Keywords | Biological Control, Entomopathogenic Nematode, Genetic Improvement and Transcriptomics |
| URL | https://www.exeley.com/journal/journal_of_nematology |