Banca de DEFESA: LUCAS SANTOS BASTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LUCAS SANTOS BASTOS
DATE: 01/04/2024
TIME: 14:00
LOCAL: Sala de aula da Pós-graduação em Fitopatologia
TITLE:

"A transcriptome analysis of the cross-stress response in Musa acuminata to water deficit and infection by the root-knot nematode Meloidogyne incognita."

KEY WORDS:

Banana, abiotic stress, drought, biotic stress, transcriptome

PAGES: 95
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

The banana crop (Musa spp.) is one of the most consumed fruits globally and is subject to both abiotic and biotic stresses. Drought and nematodes pose challenges in many producing areas, primarily due to the susceptibility of commercial cultivars to water stress and infection by the endoparasite root-knot nematode, Meloidogyne incognita. Although limited number of studies have been conducted to understand the host response to these stresses individually, there has been a lack of research on the response to combined abiotic and biotic cross stress. Therefore, the aim of this study is was characterize the root transcriptome from improved droght tolerant Musa acuminata genotype G-75 in response to drought, M. incognita infection, and the combination of both abiotic and biotic stresses “cross-stress”. Total RNA from G-075 cultivar roots was extracted 21 days after separate inoculation with M. incognita J2 juveniles, after drought stress, after "cross-stress”, and from unchallenged control plants. Physiological analysis of plants revealed moderate drought stress after 14 dyas of water deprivation, with severe drought stress after 21 days. cDNA libraris representing this later time point were sequenced using Illumina Novaseq 6000 S4 technology. High-quality sequences were mapped to the reference genome of M. acuminata spp. malaccensis var. Pahang (version 4), enabling identification and classification of differentially expressed genes (DEGs) from root tissues following nematode parasitism, water stress, and cross-stress, all in comparison to gene expression non-stressed controls. Sequencing generated a total of 359,425,623 paired-end sequences, with 287,982,958 mapped to the reference genome. These represente a total of 34,317 genes, with 5.090 DEGs identified among all treatments, in comparison to non-challenged controls. A total of 573 DEGs were identified in nematoid-infected libraries, in relation to non-inoculated controls. Enrichment analysis revealed over-represented GO terms related to catalytic activity, oxidoreductase activity, carbohydrate binding, and nucleic acid binding. In response to drought, a total of 2,834 DEGs were identified, with overrepresented GO terms comprising response to stimulus, catalytic activity and nucleic acid binding. In response to the cross-stress, a total of 1,683 DEGs were identified, of which 241 genes were common to all stresses. Here, enriched GO categories comprised response to stimulus, catalytic activity, oxidoreductase activity and nucleic acid binding. Positively regulated candidate genes for each stress were validated through RT-qPCR to confirm the RNA-seq trend. In response to M. incognita, genes encoding NLRs, RLKs, ABC transporters, as well genes involved in callose production, auxin pathways, abscisic acid (ABA), and jasmonic acid were upregulated. For water stress and cross-stress, up-regulated DEGs included those involved in responses to cold, salinity, temperature, and injuries, as well as oxidative stress, ABA, auxin, and ethylene pathways. The analysis of roots from a drought-tolerant cultivar challenged with M. incognita infection enhances our understanding of how the plant responds to biotic, abiotic and combined stresses, providing candidate genes for genetic improvement in Musa for tolerance to multiple stresses.

COMMITTEE MEMBERS:
Externa à Instituição - Andressa da Cunha Quintana Martins - EMBRAPA
Interna - 2215041 - MARISA ALVARES DA SILVA VELLOSO FERREIRA
Externo ao Programa - 1661623 - RICARDO HENRIQUE KRUGER - nullPresidente - 2644635 - ROBERT NEIL GERARD MILLER