Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Hong Kong → Genome sequencing and identification of drought-resistant genes from the evergreen desert plant Ammopiptanthus mongolicus

The Chinese University of Hong Kong (2019)

Genome sequencing and identification of drought-resistant genes from the evergreen desert plant Ammopiptanthus mongolicus

FENG, Lei

Titre : Genome sequencing and identification of drought-resistant genes from the evergreen desert plant Ammopiptanthus mongolicus

Auteur : FENG, Lei

Université de soutenance : The Chinese University of Hong Kong

Grade : Doctor of Philosophy (PhD) 2019

Résumé
Ammopiptanthusis a genus of flowering plants in the legume family. It only containstwo species, A. mongolicusand A. nanus. The former is mainly distributed in Inner Mongolia and Gansu Province of China, and the latter is restricted to partsof Xinjiang Province and is currently in an endangered status.Although grown in desert regions, Ammopiptanthuscan keepunique broad evergreen leaves even in dry and cold seasons. However, little is known about the genetic basis of these traits. Decodingthe whole genome sequence of the plant can helpstudy its stress tolerance mechanisms. Therefore, we conducted the whole genome sequencing of A. mongolicusand identified drought-resistant genes by high throughput RNAsequencing.Our preliminary results indicated that A. mongolicusis a diploid with 18chromosomes. The genome size of A. mongolicuswas predicted to be 926 Mb with 37% GC content and 66% repeat sequences. This repetitive rate could be too high to be assembled by solely usingshort-read sequencing datafromIllumina technology To assemble a high-quality draft genome, we adopted a hybrid genome sequencing strategy consisting ofthe Illumina short-readsequencing and the single-molecule real-time sequencing (Pacific Biosciences). The currentassembly of these sequencing data resulted a draft genome with 913Mb of scaffolds (N50 = 4.6Mb) and 800Mb of contigs (N50 = 720kb), respectively.The repeated sequences accounted for 69.47% of the draft genome. A total of 59,598 gene models were predicted from the draft genome.Phylogenetic analysis suggested that the divergence time of A. mongolicusand A. nanuswas 2.53 Mya.In order to identify drought-resistant genes in A. mongolicus, we have also performed a transcriptome profiling from water-stressed and well-watered plants. To verify the drought-resistant genes we identified, we chose eight genes with significant expression changes under drought treatment, cloned and over-expressedthem into the model plant Arabidopsis. Our results indicatedthat twoof the genes(ERF2and MYB84)significantlyimprovedthe drought tolerance ofthe transgenicplants.By doing all these experiments, we aim to obtain a high-quality draft genome sequence of A. mongolicusand identify genes related to drought resistance,which will help understand its drought resistancemechanisms and provide gene resources for genetic improvement of commercial crops for abiotic tolerance.

Présentation et version intégrale

Page publiée le 20 décembre 2022