Page 272 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

[P137] CHARACTERIZATION AND GENOME ASSEMBLY OF PATHOGENIC COLLETOTRICHUM
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SPP. OF MANGO. Dr. Md. Mynul Islam , Dr. Tofazzal Islam , and Dr. Andrew Sharpe . Senior Scientific
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Officer, Plant Pathology Division, Bangladesh Agricultural Research Institute, Gazipur and Postdoctoral
Fellow, Global Institute of Food Security, University of Saskatchewan, Canada; Professor, Institute of
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Biotechnology and Genetic Engineering, Bangabandhu Sheikh Muzibur Rahman Agricultural University,
Salna, Gazipur; and Bangabandhu Research Chair in Food Security, Global Institute for Food Security
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(GIFS), University of Saskatchewan, Canada
Correspondence to: mynul.islam@gifs.ca

Mango (Mangifera indica L) is a major fruit crop with an immense economical relevance in South Asian
countries, especially Bangladesh. It has high demand in the local as well as the global market due to its
taste and nutritional quality. There are many constraints of mango production in Bangladesh, however,
anthracnose disease caused by several pathogenic Colletotrichum spp. is the most damaging
postharvest issue. The disease causes about 30% yield loss in India. Molecular tools are used widely to
identify the species of Colletotrichum responsible for the disease. Twenty five isolates of Colletotrichum
spp. (C. gloeosporioides, C. asianum and C.siamense) from mango fruits were collected, isolated and
purified from 11 mango growing regions in Bangladesh during May 2023 to July 2023. Pathogenicity tests
of the isolated pure cultures were conducted using BARI mango-3 as a host. DNA of the isolates were
extracted, ITS rDNA gene was amplified, sequenced and blasted to confirm the pathogen species. Whole
genome sequencing of the Colletotrichum spp. isolates is being carried out using an Oxford MinION long
read sequencer. Genome assembly and gene annotation will be undertaken, and unique primers will be
designed to identify species and for the development of a rapid diagnostic kit.

[P138] BRASSINOSTEROIDS AND SALICYLIC ACID MUTUALLY ENHANCE ENDOGENOUS
CONTENT AND SIGNALING TO SHOW A SYNERGISTIC EFFECT ON PATHOGEN RESISTANCE IN
ARABIDOPSIS THALIANA. Jeehee Roh, Yeon Ju Park, Ji-Hyun Youn, and Seong-Ki Kim. Department
of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea
Correspondence to: skkimbio@cau.ac.kr

The crosstalk mechanism regulating content and signal transduction between brassinosteroids (BRs) and
salicylic acid (SA) for plant defense was investigated in Arabidopsis. Compared to the wild type, an
increased bacterial resistance was observed in bzr1-1D, a dominant mutant of the BR transcription factor
BZR1. In bzr1-1D, SA biosynthetic gene ICS1 expression and endogenous SA content greatly increased
upon Pst DC3000 infection, and the direct binding of BZR1 to the ICS1 promoter was confirmed through
EMSA and ChIP. In bzr1-1D where NPR1 expression was almost absent, expression of PR genes was
increased, and both BZR1 and PR5 expressions increased after SA treatment. EMSA and ChIP verified
that BZR1 binds directly to the cis-element present in the PR5 promoter and a pull-down assay showed
that TGAs, SA transcription factors upstream of PR genes, interact with BZR1 at the protein level. Crude
enzyme assays demonstrated that BR C-6 oxidase activity, a CYP85A1 function, greatly increased during
Pst DC3000 infection. In the tga1 tga4 double mutant lacking SA transcription factors TGA1 and TGA4,
BR biosynthetic gene CYP85A1 expression was significantly reduced. EMSA and ChIP confirmed that
both TGA1 and TGA4 bind to the cis-element present in the CYP85A1 promoter, and castasterone (CS),
a bio-active BR, was significantly reduced in tga1 tga4. Taken together, the upregulation of ICS1
expression by BZR1 and CYP85A1 expression by TGA1/4 mutually enhanced endogenous level of BR
and SA in Arabidopsis. Furthermore, TGAs and BZR1 interaction at the protein level induces SA-induced
immunity through the upregulation of PR5 expression, increasing bacterial resistance in the plant. These
results explain the mutual control mechanisms of the synergistic effects BR and SA have on plant
defense and confirm BR’s effect on plant defense and growth promotion in A. thaliana.

[P139] APPLICATION OF PACBIO KINNEX RNA KIT TO SOIL DNA SAMPLES FOR 16S AND ITS
RRNA AMPLICONS FROM CROPLANDS. Sung-Jong Lee, Tiffany Chin, Janice Bamforth, Niradha
Withana Gamage, and Sean Walkowiak. Grain Research Laboratory, Canadian Grain Commission, 196
Innovation Drive, Winnipeg, MB, Canada, R3T 2N2
Correspondence to: sung-jong.lee@grainscanada.gc.ca

Soil microbiome studies using amplicon-based metagenomics for 16S and ITS rRNA are widely
conducted in various soil types, including croplands. 16S and ITS sequences act like barcodes that can

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