Development of a High-Resolution Multi-Locus Microsatellite Typing Method for Colletotrichum gloeosporioides

Patil

2021

Preprint

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The conidia of a hemibiotrophic fungus Colletotrichum gloeosporioides can conventionally form germ tube (GT) and develop in to a fungal colony, while under certain conditions, they tend to get connected with each other through conidial anastomosis tube (CAT) so as to share the nutrients. CAT fusion is believed to be responsible for generation of genetic variations in few asexual fungi, which appears problematic for effective fungal disease management. The physiological and molecular mechanism underlying the GT versus CAT formation remained unexplored. In the present study, we have deciphered the decision switch responsible for GT formation versus CAT fusion in C. gloeosporioides. GT formation occurred at high frequency in the presence of nutrients, while CAT fusion was found to be higher in absence of nutrients. Younger conidia were found to form GT efficiently, whilst older conidia preferentially formed CAT. Whole transcriptome analysis of GT and CAT fusion revealed differential molecular requirements for these two processes. We identified 11050 and 9786 differentially expressed genes (DEGs) in GT and CAT, respectively. A total 1567 effector candidates were identified, of them 103 and 101 were uniquely secreted during GT and CAT formation respectively. Genes coding for cell wall degrading enzymes, germination, hyphal growth, host-fungus interaction and virulence were up-regulated during GT formation. Whilst, genes involved in stress response, cell wall remodelling, membrane transport, cytoskeleton, cell cycle, and cell rescue were highly up-regulated during CAT fusion. To conclude, the GT and CAT fusion were found to be mutually exclusive processes, requiring differential physiological conditions and sets of DEGs in C. gloeosporioides. This will help to understand the basic CAT biology in the genus Colletotrichum.

Section: Introductionsupporting

confidence: 53%

Deciphering the differential physiological and molecular requirements for conidial anastomosis tube fusion and germ tube formation inColletotrichum gloeosporioides

Patil

2021

Preprint

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“…Among different species, C. gloeosporioides and C. siamense cause anthracnose in a wide range of host plants such as fruit, vegetable and ornamental plants (Cai et al, 2009;Freeman et al, 1996;Hyde et al, 2009;Jayawardena, 2018;Sharma et al, 2013). We have shown that there is a high level of genetic diversity in C. gloeosporioides isolates in India (Mehta et al, 2017). Our observation also corroborates with a series of studies published on genetic and pathogenic diversity of C. gloeosporioides (Denoyes-Rothan et al, 2003;Nova et al, 2011;Weeds et al, 2003).…”

Section: Introductionmentioning

confidence: 72%

Quorum sensing-mediated inter-specific conidial anastomosis tube fusion between Colletotrichum gloeosporioides and Colletotrichum siamense.

2020

Preprint

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Many plant pathogenic filamentous fungi undergo fusion of conidia through conidial anastomosis tubes (CATs), which is believed to facilitate horizontal gene transfer between species. We discovered a remarkable inter-specific conidial anastomosis tube (CAT) fusion between two important plant fungal pathogens Colletotrichum gloeosporioides and Colletotrichum siamense. In an In vitro assay, under no selection pressure, the inter-specific CAT fusion was preferred with higher frequency (25%) than intra-specific CAT fusion (11%). Different stages of CAT fusion viz. CAT induction, homing, and fusion were observed during this inter-specific CAT fusion. The CAT fusion was found to be higher in absence of nutrients and in the presence of physiological stresses. This CAT fusion involved a quorum sensing phenomenon, wherein the CAT induction was dependent on conidial density and the secreted putative quorum sensing molecules were found to be lipid based in nature. Movement of nuclei, mitochondria, lysosomes and lipid droplets were observed during the CAT fusion. Post CAT fusion, the resulting conidia gave rise to putative recombinants with variable colony characteristics as compared to their parental strains. Few recombinants showed variable AFLP banding pattern compared to their parental strains, thereby suggesting a possible genetic exchange between the two species through CAT fusion. The recombinants exhibited variable fitness under different stress conditions. Our study signifies possible role of inter-specific CAT fusion in generation of genetic and phenotypic diversity in these fungal pathogens.

“…Among different species, C. gloeosporioides and C. siamense cause infection in a wide range of host plants (Cai et al 2009 ; Freeman et al 1996 ; Hyde et al 2009 ; Jayawardena 2018 ; Sharma et al 2013 ). We have previously reported a high level of genetic diversity in C. gloeosporioides isolates in India (Mehta et al 2017 ). Our observation also corroborates with earlier studies which discussed genetic and pathogenic diversity in C. gloeosporioides (Denoyes-Rothan et al 2003 ; Nova et al 2011 ; Weeds et al 2003 ).…”

Section: Introductionmentioning

confidence: 98%

Quorum sensing-mediated inter-specific conidial anastomosis tube fusion between Colletotrichum gloeosporioides and C. siamense

2021

IMA Fungus

Self Cite

Many plant pathogenic filamentous fungi undergo fusion of conidia through conidial anastomosis tubes (CATs), which is believed to facilitate horizontal gene transfer between species. We discovered a remarkable inter-specific CAT fusion between two important plant fungal pathogens Colletotrichum gloeosporioides and C. siamense. In an invitro assay, under no selection pressure, the inter-specific CAT fusion was preferred with higher frequency (25% ± 5%) than intra-specific CAT fusion (11% ± 3.6%). Different stages of CAT fusion viz. CAT induction, homing, and fusion were observed during this inter-specific CAT fusion. The CAT fusion was found to be higher in absence of nutrients and under physiological stresses. This CAT fusion involved a quorum sensing phenomenon, wherein the CAT induction was dependent on conidial density and the putative quorum sensing molecule was extractable in chloroform. Movement of nuclei, mitochondria, and lipid droplets were observed during the CAT fusion. Post CAT fusion, the resulting conidia gave rise to putative heterokaryotic progenies with variable colony characteristics as compared to their parental strains. Few heterokaryons showed variable AFLP banding pattern compared to their parental strains, thereby suggesting a possible genetic exchange between the two species through CAT fusion. The heterokaryotic progenies exhibited varied fitness under different stress conditions. Our study illustrated a possible role of inter-specific CAT fusion in generation of genetic and phenotypic diversity in these fungal pathogens.