Banca de DEFESA: MUHAMMAD SIDDIQUE AFRIDI

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: MUHAMMAD SIDDIQUE AFRIDI
DATA: 27/01/2023
HORA: 08:00
LOCAL: Defesa remota via Google Meet
TÍTULO:

ONE OR MILLIONS: HOW MUCH A MICROBIOLOGICALLYBUFFERED SOIL WITHSTAND CHEMICAL AND BIOLOGICAL PESTICIDES

PALAVRAS-CHAVES:

Soil microbiome manipulation, soil-borne disease, biological control agent (BCA), Bio-pesticides, sustainable disease management

PÁGINAS: 328
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitossanidade
ESPECIALIDADE: Fitopatologia
RESUMO:

Disease suppressive soils substantially contribute to plant protection against various soil-borne plant pathogens such as bacteria, fungi, oomycetes, and nematodes. The foundation of specific disease suppression in most soils affiliates commonly to soil microbial communities. Therefore, the soil microbiota of suppressive soils is considered one of the radical factors contributing to disease suppressiveness against soil-borne diseases. To date, a multitude of microbial taxa and genes have been documented as central players in participating disease suppressiveness of soils. Still, the dominant genera, their sensitivity to alien biocontrol advocacy, agrochemicals and the complexity of microbiome interactions and their underlying mechanisms remain elusive for most disease suppressive soils. The main objective of the current research was to manipulate the existing suppressive soil microbiome through the introduction of various biological control agents and agrochemicals to explore the microbiome functionality towards soil-born (root-knot) nematodes disease. Suppressive soil assay revealed that natural soil significantly reduced galls-1 (14.25%) and egg masses (74.85%) in relation to sterilized soil. Intriguingly suppressive soil microbiome manipulation by biological control agent Bacillus sp. BMH intervened in the microbial functions and reduced its suppressiveness. BMH inoculated suppressive soil significantly increased the galls-1 and eggs-1 32% and 47.96% respectively as compared to un-inoculated suppressive soil. Interestingly, suppressive soil slurry blending with antibiotics and fungicide significantly modulated the soil microbiome functionality. Soil slurry mixed with antibiotics and fungicide significantly increased the number of galls-1 174.23% and 87.79% respectively as compared to the untreated slurry. Following the same pattern, antibiotics and fungicide inoculation significantly increased the number of egg masses by 276.24% and 38.17% respectively as compared to the untreated slurry. Biocontrol based on bacteria such as Quatrzo(Bacillus subtilis; Bacillus licheniformis), Biobac(Bacillus subtilis), Onix (Bacillus methylotrophicus) and Rizos(Bacillus subtilis) turbulent the soil microbiome performance and insignificantly increased the galls and eggs mass index in relation to suppressive soil. To understand and explore the intrinsic fundamental candidates of the disease suppressive soil, the research promoted to the next level and recovered the responsible candidates from the reported suppressive soil and deciphered their potential role against root-knot nematode (RKN) Meloidogyne incognita in the tomato plant. A total of 42 bacterial strains were isolated from the suppressive soil and 18 of them were identified with high potential to control M. incognita. The isolates were sequenced based on 16S rRNA and identified 6 different genera namely Bacillus, Pseudomonas, Leclercia, Paenarthrobacter, Pantoea, and Exiguobacterium. Eighteen bacteria of six different genera were selected based on preliminary screening. The plant was inoculated with strains Bacillus sp. P10, Bacillus sp. P16, Bacillus sp. P19, and Bacillus sp. P21 significantly reduced the root galling 47% and the significant average reduction of egg mass was recorded 75.5% in relation to control. Three Pseudomonas sp. P17, Pseudomonas sp. X11, and Pseudomonas sp. X18 exhibited high biocontrol efficacy and significantly reduced the galls and egg masses 54% and 75% in both trials as compared to the control. The isolates such as Leclercia sp. P12, Leclercia sp. P18 and Leclercia sp. P20 exhibited high potential and consistency in controlling gall and egg biomass index in both trials the significant reduction was observed in root galling 47% and egg biomass index 70% as compared to the untreated plants. The bacterial strain, Paenarthrobacter sp. X12 showed consistency and maintained the biocontrol capability and significantly reduced the number of galls and egg biomass 57% and 89% respectively in rlation to uninoculated plant. Additionally, all six genera' volatile organic compounds (VOCs) and metabolites in cell-free supernatants had significant effects against the plant pathogens M. incognita, Fusarium oxysporum, and Rhizoctonia solani, but only five strains Pseudomonas sp. P7, Pseudomonas sp. X11, Bacillus sp. P10, Bacillus sp. P21, and Leclercia sp. P12 significantly inhibited the growth of Ralstonia solanacearum. Moreover, all bacterial isolates inherit nematicidal activities and dramatically reduced the egg hatching. These findings recommend that exogenous biological control agents, biostimulants and agrochemicals massively perturb the microbiome structure, composition, ecological and biological activities and detract or infertile the endogenous microbiota functionality.

MEMBROS DA BANCA:
Externo à Instituição - SAMUEL JÚLIO MARTINS - UF (Membro)
Interno - RAFAELA ARAÚJO GUIMARÃES - UFLA (Suplente)
Externo à Instituição - LUCIANA CORDEIRO DO NASCIMENTO - UFPB (Membro)
Externo à Instituição - JÚLIO CARLOS PEREIRA DA SILVA - UFSM (Suplente)
Interno - JORGE TEODORO DE SOUZA (Membro)
Presidente - FLAVIO HENRIQUE VASCONCELOS DE MEDEIROS (Membro)
Externo à Instituição - AMNA - Q.A.U (Membro)