Normal view MARC view ISBD view

Novel strains of Metarhizium anisopliae sorokin.(Ascomycota:sordariomycetes) with enhanced abiotic stress tolerance (Record no. 291164)

MARC details
000 -LEADER
fixed length control field	06680nam a22002177a 4500
082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER
Classification number	632.6
Item number	SRE/NO PG
100 ## - MAIN ENTRY--PERSONAL NAME
Personal name	Sreelakshmi, U K
245 ## - TITLE STATEMENT
Title	Novel strains of Metarhizium anisopliae sorokin.(Ascomycota:sordariomycetes) with enhanced abiotic stress tolerance
260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT)
Place of publication, distribution, etc	Vellanikkara
Name of publisher, distributor, etc	Department of agricultural entomology, college of agriculture
Date of publication, distribution, etc	2023
300 ## - PHYSICAL DESCRIPTION
Extent	117,xxxiip.
502 ## - DISSERTATION NOTE
Dissertation note	MSc
520 3# - SUMMARY, ETC.
Abstract	Novel strains of Metarhizium anisopliae Sorokin. (Ascomycota: <br/>Sordariomycetes) with enhanced abiotic stress tolerance<br/>Abstract<br/>The green muscardine fungus, Metarhizium anisopliae Sorokin is widely used in the <br/>management of various crop pests. However the efficacy of M. anisopliae in the field <br/>is often inconsistent, mainly due to the environmental stresses such as temperature <br/>extremes, drought, UV radiation, etc. To circumvent these hurdles, the present study <br/>was undertaken to develop novel strains of M. anisopliae with enhanced <br/>environmental stress tolerance. <br/>The Metarhizium isolates, EKM2, CKD, and M4 were collected from the <br/>repository maintained at the Department of Agricultural Entomology and were <br/>screened for their temperature and drought tolerance. The isolate EKM2 recorded the <br/>highest mycelial weight (6.221g), while the isolate M4 recorded the least mycelial <br/>weight (0.328 g) and the least sporulation at the highest temperature of 380C. The <br/>screening for drought tolerance was conducted at various levels of Polyethylene <br/>glycol (PEG) concentrations in which the isolate CKD has shown higher biomass <br/>(2.172 g) with higher sporulation, while isolate M4 recorded the lowest mycelial<br/>weight (1.336 g) at the maximum PEG concentration of 39 per cent. The three <br/>selected isolates of M. anisopliae (CKD, EKM2 and M4) were subjected to further <br/>experiments.<br/>The Metarhizium isolates (CKD, EKM2 and M4) selected from the <br/>preliminary screening were continuously subjected to temperature stress treatments <br/>starting from 35oC to 42oC. At the highest temperature of 41oC, the isolate, EKM2 <br/>recorded the highest mycelial weight (1.336 g), number of colonies (18.667103<br/>cfu/ml), number of spores (0.783 X 10 7<br/>/ml), spore size (3.470 µm) and mycelial <br/>thickness (3.07 µm). At the same temperature, the isolate, M4 recorded the lowest <br/>mycelial weight (0.63g), number of colonies (3 cfu/ml), number of spores (0.217 X 10 <br/>7<br/>/ml), spore size (1.637 µm), and mycelial thickness (2.65 µm). Hence EKM2 has <br/>been identified as the thermo-tolerant isolate and M4 as the susceptible one. The <br/>thermo-tolerant isolate EKM2 was grown continuously for 6 successive generations at <br/>the same temperature level of 41oC in order to stabilize the stress tolerance.<br/>The Metarhizium isolates (CKD, EKM2, and M4) selected from the <br/>preliminary drought screening experiment were also continuously subjected to <br/>drought-inducing treatments at PEG concentrations starting from 25 to 40 per cent. <br/>At the highest level of PEG concentration (40 %), the isolate CKD showed higher <br/>mycelial weight (3.365 g), spore count (0.323X 107 /ml)), number of colonies (4 X <br/>103<br/>colonies/ ml), spore size (3.15 µm), and mycelial thickness (2.723µm). The <br/>isolate, M4 recorded the lowest mycelial weight (0.808g), number of colonies (2<br/>cfu/ml), spore count (0.243 spores/ml), spore size (4.493 µm), and mycelial thickness <br/>(2.543 µm) at the same PEG concentration. Hence isolate CKD is identified as <br/>drought tolerant and M4 as susceptible. The drought-tolerant isolate, CKD was grown <br/>continuously for 6 successive generations at the same PEG concentration level of 40 <br/>per cent in order to stabilize the stress tolerance.<br/>The selected tolerant isolates were evaluated against wax moth larva (Galleria <br/>mellonella) to identify their biocontrol efficacy. Isolate EKM2 has shown cent per <br/>cent mortality at the dosage of 108<br/>and 109<br/>spores/ml on the 9th day after treatment. At <br/>the highest dosage of 1x 109<br/>spores/ ml, the isolate CKD recorded a lower LT50 (5.099 <br/>days) value, and isolate M4 recorded the highest LT50 (6.124 days) value. The isolates <br/>EKM2 and CKD were found to be more virulent while M4 was less virulent.<br/>The thermo-tolerant isolate, EKM2 recorded a total protein content of 0.354 <br/>mg/ml, and the drought-tolerant isolate (CKD) recorded a total protein content of <br/>0.373 mg/ml. The thermo-tolerant isolate EKM2 has shown a trehalose content of <br/>1.954 mg/min/g tissue weight which was significantly higher compared to the control <br/>(1.074 mg/min/g tissue weight). The trehalose content in the drought-tolerant isolate <br/>CKD (1.970 mg/min/g) was also higher when compared to the control (1.224 <br/>mg/min/g). The catalase activity ranged between 0.237 EU/min/mg proteins in the <br/>control to 0.386 EU/min/mg protein in the thermo-tolerant isolate EKM2, while the <br/>catalase activity of the drought-tolerant isolate, CKD was 0.384 c protein which was <br/>higher when compared to its control (0.240 EU/min/mg protein). The thermo-tolerant <br/>isolate recorded a peroxidase activity of 0.0230 EU/min/g tissue and that of droughttolerant isolate CKD was 0.0236 EU/min/g tissue weight. The protease activity of <br/>thermo-tolerant isolate CKD was 0.490 EU/min/mg protein and that of the droughttolerant isolate was 0.621 EU/min/mg protein. <br/>At 25 minutes of reaction, the thermo-tolerant and drought-tolerant isolates <br/>have shown higher lipase activity (10.000 µmol fatty acid/ml and 11.00 µmol fatty <br/>acid/ml respectively) when compared to their respective controls. On the 5th day, both <br/>the thermo-tolerant and drought- tolerant isolates recorded significantly higher <br/>chitinase activity (1.140 µg of N- acetyl glucose amine/min/ml of broth and 3.062 µg <br/>of N- acetyl glucose amine/min/ml of broth respectively) than their controls.<br/>The temperature induction had up-regulated heat shock proteins of 25 kDa and <br/>35 kDa in heat-induced isolate EKM2. The isolate also expressed heat shock proteins <br/>in the range of 100 kDa molecular weight. Drought tolerant isolate (CKD) on the <br/>other hand did not show the presence of any heat shock protein when compared to the <br/>control.<br/>The study could develop isolates of M. anisopliae which are tolerant to <br/>temperature and drought stress, with high virulence as well as higher biochemical <br/>activity
650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM
Topical term or geographic name as entry element	Metarhizium anisopliae
650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM
Topical term or geographic name as entry element	Temperature tolerance
650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM
Topical term or geographic name as entry element	Suitability of galleria mellonella as host
650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM
Topical term or geographic name as entry element	Colloidal chitin preparation
650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM
Topical term or geographic name as entry element	Agricultural entomology
700 ## - ADDED ENTRY--PERSONAL NAME
Personal name	Deepthy, K B(Guide)
856 ## - ELECTRONIC LOCATION AND ACCESS
Uniform Resource Identifier	https://krishikosh.egranth.ac.in/handle/1/5810214178
942 ## - ADDED ENTRY ELEMENTS (KOHA)
Source of classification or shelving scheme	Dewey Decimal Classification
Item type	Theses

Holdings
Not for loan	Collection code	Home library	Current library	Shelving location	Date acquired	Full call number	Barcode	Date last seen	Koha item type
Not For Loan	Thesis	KAU Central Library, Thrissur	KAU Central Library, Thrissur	Theses	11/04/2024	632.6 SRE/NO PG	175967	11/04/2024	Theses