Red Rot Disease Of Sugarcane Research Articles

Assessment and management of diverse isolates of Colletotrichum falcatum associated with red rot disease in sugarcane

Assessment and management of diverse isolates of Colletotrichum falcatum associated with red rot disease in sugarcane

A Novel Approach for Red Rot Disease Detection in Sugarcane Plants Using Transfer Learning Based VGG16 Model

Red rot in sugarcane is a devastating fungal disease caused by Colletotrichum falcatum. It leads to wilting, red discoloration, and yield losses, which can impact sugar production globally. Red rot hampers sugarcane production, causing yield reductions, and economic losses, and affecting the nation’s sugar industry demanding stringent disease management strategies. There is a need of a system that detects the red rot disease at an early stage before it spreads. Transfer learning enhances agricultural models, leveraging pre-trained data for improved crop predictions, resource optimization, and sustainability. In this article, we have proposed a transfer learning-based VGG16 model for the detection of red rot disease in sugarcane on a large dataset. The model achieves a remarkable 98.85% accuracy and an F1 score of 0.93 in early red rot detection in sugarcane. This work underscores the potency of leveraging re-trained models for crop disease identification, offering a promising avenue for proactive disease management. This research marks a substantial step towards enhancing crop yield and sustainability, presenting an accessible and impactful technological solution for early disease detection in sugarcane, ultimately benefiting agricultural practices.

Suppression of Sugarcane Red Rot Disease through Its Rhizospheric Mycoflora

Red rot disease of sugarcane is so devastating in nature that it has been referred to as “cancer of sugarcane”. The sugar industry in India suffered losses more than 500 million US dollars every year due to red rot. So, there is a need to look over the management and control of the disease. Biological control method is an alternative method of chemical pesticides which are an innovative, cost effective and eco-friendly approach. Soil samples were collected from sugarcane rhizosphere of four different varieties viz., CoPk 05191 and CoLk 94184 (resistant to red rot) and CoJ 64 and Co 1148 (susceptible to red rot) planted at ICAR-Indian Institute of Sugarcane Research, Lucknow experimental farm. The samples were subjected for the isolation of rhizospheric mycoflora on Potato Dextrose Agar media and antagonistic activities of the isolates were tested against red rot pathogens (Cf 07, Cf 08 and Cf 09). Isolates showing more than 50 % inhibition with all the three pathotypes (Cf 07, Cf 08 and Cf 09) were selected for further study. Among the twelve selected isolates used for field experiment for the management of red rot, isolate T16 was found to be highly effective. The suppression of red rot offered by rhizospheric isolates is probably due to induced systemic resistance in sugarcane plants or by the enzymatic action of metabolites produced by the rhizospheric mycoflora. The different levels of red rot infected seed cane viz., 5%, 10%, 15%, 20%, 25%, 30%, 35% and 40% were treated with MHAT and planted along with healthy seed canes, infected seed canes, as a control to work out the losses caused by different level of red rot seed infection. The result revealed that a yield loss was recorded with the infected seed. The losses were directly proportionate with the level of red rot infected seed.

MAPK signaling pathway orchestrates and fine-tunes the pathogenicity of Colletotrichum falcatum

Colletotrichum falcatum is the causal organism of red rot, the most devastating disease of sugarcane. Mitogen-activated protein kinase (MAPK) signaling pathway plays pivotal role in coordinating the process of pathogenesis. We identified eighteen proteins implicated in MAPK signaling pathway in C. falcatum, through nanoLCMS/MS based proteomics approach. Twelve of these proteins were the part of core MAPK signaling pathway, whereas remaining proteins were indirectly implicated in MAPK signaling. Majority of these proteins had enhanced abundance in C. falcatum samples cultured with host sugarcane stalks. To validate the findings, core MAPK pathway genes (MAPKKK-NSY1, MAPK 17-MAPK17, MAPKKK 5-MAPKKK5, MAPK-HOG1B, MAPKKK-MCK1/STE11, MAPK-MST50/STE50, MAPKK-SEK1, MAPKK-MEK1/MST7/STE7, MAPKK-MKK2/STE7, MAPKKK-MST11/STE11, MAPK 5-MPK5, and MAPK-MPK-C) were analyzed by qPCR to confirm the real-time expression in C. falcatum samples cultured with host sugarcane stalks. The results of qPCR-based expression of genes were largely in agreement with the findings of proteomics. String association networks of MAPKK- MEK1/MST7/STE7, and MAPK- MPK-C revealed strong association with plenty of assorted proteins implicated in the process of pathogenesis/virulence. This is the novel and first large scale study of MAPK proteins in C. falcatum, responsible for red rot epidemics of sugarcane various countries. Key messageOur findings demonstrate the pivotal role of MAPK proteins in orchestrating the pathogenicity of Colletotrichum falcatum, responsible devastating red rot disease of sugarcane. SignificanceOur findings are novel and the first large scale study demonstrating the pivotal role of MAPK proteins in C. falcatum, responsible devastating red rot disease of sugarcane. The study will be useful for future researchers in terms of manipulating the fungal pathogenicity through genome editing.

Molecular diagnosis of red rot of sugarcane in Pakistan and in vitro control of isolated pathogen using rhizobacteria

Sugarcane (Saccharum officinarum L.) is a key cash crop, and its production is influenced by a variety of phytopathogens in different parts of the world. During consecutive field surveys, sugarcane stalks with red rot symptoms were observed in three provinces of Pakistan (Punjab, Sindh, and Khyber Pakhtunkhwa). Cane samples with visible symptoms were plated on Potato Dextrose Agar (PDA) media. Morphological and microscopic observations identified this pathogen as Colletotrichum falcatum. Comparative molecular study of amplified sequences of β-tubulin (Bt) and Actin (ACT) genes showed 100% similarity and ITS sequence showed 99% similarity with C. falcatum. For in vitro control of red rot, eight bacterial strains from the rhizosphere of sugarcane were isolated. These strains showed variable growth inhibition of C. falcatum in dual culture method. Among all tested strains, Bacillus amyloliquefaciens and B. altitudinis exhibited best antifungal activities. Based on these results, tested bacterial strains (B. amyloliquefaciens and B. altitudinis) can be recommended as effective biocontrol agents to manage red rot disease of sugarcane.

Evaluation of elite sugarcane clones/varieties against red rot disease (Colletotrichum falcatum) and their suitability in crop improvement programme

Abstract. To manage red rot disease in sugarcane, several methods like use of bio-control agents, hot water and hot air treatment of setts, chemical fungicides, various cultural practices like use of disease free setts, rouging, crop rotation, irrigation management, avoiding rationing, etc. are practised. But none of the practices are able to control the disease. The most viable strategy is to manage through host plant resistance. Thus, a field experiment was conducted for two consecutive years during 2019 and 2020 at the Research Farm of Sugarcane Research Station, Bethuadahari (West Bengal), India to evaluate some elite sugarcane clones/varieties against red rot disease. The elite clones/varieties were laid out in Completely Randomized Block Design with a plot size of 2R x 6m x 0.90m with 2 replications and two red rot pathotypes Cf 07 and Cf 08 were used for artificial inoculation in plug and nodal method. The experiment revealed that the sugarcane clones CoP 16436, CoP 16437, CoP 16438, CoLk 16466, CoLk 16467, CoLk 16468, CoSe 16451, CoP 16439, CoP 16440, BO 156, CoLk 16469, CoLk 16470, CoLk 16471, CoSe 16452, CoSe 16453, CoSe 16454, CoP 17436, CoP 17437, CoP 17438, CoP 17440, CoP 17441, CoSe 17451, CoSe 16455, CoSe 16456, CoP 17444, CoP 17446 and CoSe 17452 were found as moderately resistant (MR) in plug method and resistant (R) in nodal method to both pathotypes and can be used for further evaluation in subsequent varietal developmental as well as breeding programme. The popular sugarcane varieties, namely CoLk 94184, CoSe 01421, BO 91, CoP 9301 and CoP 06436 were found as moderately resistant (MR) in plug method and resistant (R) in nodal method and can be continued for commercial cultivation as well as red rot breeding programme. As the existing popular variety CoSe 95422 was found moderately susceptible (MS) in plug method and susceptible (S) in nodal method to Cf 07 and Cf 08 red rot pathotypes, thus the variety must be discarded from commercial cultivation with immediate effect.

A SURVEY ON A PLANT DISEASE, RED ROT OF SUGARCANE (Collectotricum Falcatum) ON BAITADI DISTRICT

Our Survey area is Dilasaini, Ward no.5 of Baitadi District where sugarcane cultivation is widely done in almost all the households of that area and their main problem was red rot disease of sugarcane. We had collected data by using semi structured questionnaire and key informant survey (KIS) was also conducted. Pilot testing was also done to check the accuracy. Data entry was done using MS Excel and descriptive analysis was done using IPM SPSS V.20. Among the diseases of plants, Collectotricum falcatum is highly prevalent in Baitadi and has affected the sugarcane cultivation and production. It not only reduce the production but also causes decline in quality of sugarcane produce and our survey is based on status of people residing there, sugarcane status and Collectotrichum presence, its causes, losses and the expectations of farmers regarding its management. We found that 81.81% were male headed and 18.18% were female headed, 59.09% were Brahmins, 22.72% were Chhetris, 12.12% were Yogis and 6.06% were Dalits. 36.36% have less than 5 ropani land, 40.905 have between 5 to 10 ropani and 22.72% have more than 10 ropani. 83.33% have given prority to jaggery production followed by16.67% to juice extractions and 0% in sugar production. We found that 40.90% households has faced loss more than 60%, 40.90% household facing losses between 30-60% and 18.18% households were facing loss around 10-30%. 68.18% respondents have expectations priority on provision of subsides, 16.67% respondents have on timely availability of planting material, 6.06 % respondents have on fungicide availability, 4.54% have on irrigation facility and remaining 3.03% have on provision of research facility.

PSEUDOMONAS FLUORESCENS: POTENTIALITY AGAINST RED ROT DISEASE OF SUGARCANE

Red rot disease of sugarcane caused by Colletotrichum falcatum is one of the oldest known, most widespread and threatening diseases in sugarcane which should be controlled/managed as early as possible before it ruin the crop. There are multifarious strategies for red rot disease management, including chemical, physical methods and use of resistant varieties. Strains of fluorescent Pseudomonas are known to suppress the soil borne inoculum of C. falcatum surviving in the rhizosphere and to induce systemic resistance against red-rot. Especially Pseudomonas flourescens has high efficacy against red rot pathogen and enhances cane and sugar yields. Thus, it is essential to screen and evaluate bacterial strains which could be exploited for the management of red rot disease in sugarcane.

Multi-stress tolerant PGPR Bacillus xiamenensis PM14 activating sugarcane (Saccharum officinarum L.) red rot disease resistance

Sustainability in crop production has emerged as one of the most important concerns of present era's agricultural systems. Plant growth promoting bacteria (PGPB) has been characterized as a set of microorganisms used for enhancing plant growth and a tool for biological control of phytopathogens. However, the inconsistent performance of these bacteria from laboratory/greenhouse to field level has emerged due to prevailing abiotic stresses in fields. Sugarcane crop encounters a combination of biotic and abiotic stresses during its long developmental stages. Nevertheless, the selection of antagonistic PGPB with abiotic stress tolerance would be beneficial for end-user by the successful establishment of product with required effects under field conditions. Stress tolerant Bacillus xiamenensis strain (PM14) isolated from the sugarcane rhizosphere grown in the fields was examined for various PGP activities, enzyme assays, and antibiotic resistance. Strain was screened for in vitro tolerance against drought, salinity, heat stress, and heavy metal toxicity. Inhibition co-efficient of B. xiamenensis PM14 was also calculated against six phyto-pathogenic fungi, including Colletotrichum falcatum (53.81), Fusarium oxysporum (68.24), Fusarium moniliforme (69.70), Rhizoctonia solani (71.62), Macrophomina phaseolina (67.50), and Pythium splendens (77.58). B. xiamenensis is reported here for the first time as the rhizospheric bacterium which possesses resistance against 12 antibiotics and positive results for all in vitro PGP traits except HCN production. Role of 1-aminocyclopropane-1-carboxylate deaminase in the amelioration of biotic and abiotic stress was also supported by the amplification of acds gene. Moreover, in vitro and in vivo experiments revealed B. xiamenensis as the potential antagonistic PGPR and bio-control agent. Results of greenhouse experiment against sugarcane red rot indicated that inoculation of B. xiamenensis to sugarcane plants could suppress the disease symptoms and enhance plant growth. Augmented production of antioxidative enzymes and proline content may lead to the induced systemic resistance against red rot disease of sugarcane. Thus, the future application of native multi-stress tolerant bacteria as bio-control agents in combination with current heat, drought, salinity, and heavy metal tolerance strategy could contribute towards the global food security.

Evaluation of antagonistic activity and mechanisms of endophytic yeasts against pathogenic fungi causing economic crop diseases.

This work aimed to evaluate in vitro antagonistic activities and mechanisms of endophytic yeasts against phytopathogenic fungi. A total of 407 yeast strains isolated from tissue of rice, corn, and sugarcane leaves were evaluated for their antagonistic activities against ten phytopathogenic fungi. Only strains of Wickerhamomyces anomalus and Kodamaea ohmeri were found to inhibit the growth of phytopathogenic fungi. Wickerhamomyces anomalus (seven strains) showed antagonistic activity against Curvularia lunata (cause of dirty panicle disease of rice), three Fusarium moniliforme strains (cause of bakanae disease of rice, stalk rot disease of corn, and red rot disease of sugarcane), and Rhizoctonia solani (cause of sheath blight disease of rice). Whereas four Kodamae ohmeri strains inhibited growth of F. moniliforme (cause of bakanae disease of rice). Antagonistic mechanisms of W. anomalus were based on the production of volatile organic compounds (VOCs) (mainly 3-methyl-1-butyl acetate and 3-methyl-1-butanol), fungal cell wall-degrading enzymes (β-1,3-glucanase and chitinase), and siderophores as well as phosphate and zinc oxide solubilization. As for K. ohmeri, the production of VOCs (mainly 3-methyl-1-butanol), β-1,3-glucanase and chitinase were hypothesized as possible mechanisms. The antagonistic activity of W. anomalus against these phytopathogenic fungi and of K. ohmeri against F. moniliforme, and the analysis of the VOCs produced by K. ohmeri are reported for the first time. Two W. anomalus strains, DMKU-RE13 and DMKU-CE52, were evaluated for controlling rice sheath blight disease caused by R. solani in rice plants in the greenhouse and found to suppress the disease 55.2-65.1%, whereas 3% validamycin suppressed this disease by 88.5%.

Trichoderma-Mediated Suppression of Red Rot of Sugarcane Under Field Conditions in Subtropical India

Thirty-eight isolates of Trichoderma spp. established from the rhizosphere of sugarcane were characterized using a multiplex PCR assay and further assessed for the production of hydrolytic enzymes chitinase and cellulase. The results of multiplex PCR assay successfully identified 29 isolates and revealed T. harzianum to be the predominant species (21 isolates) in sugarcane rhizosphere followed by T. longibrachiatum (8 isolates). In enzymatic assays, chitinase production was recorded in 18 isolates and cellulase production observed in 17 isolates. However, there was a considerable variability in both chitinase and cellulase production potential across the isolates. Three T. longibrachiatum isolates (STr-52, STr-83 and STr-108) exhibited high production of both chitinase and cellulase. Talc formulation of two promising isolates (STr-83 and STr-108) was prepared and evaluated in the field conditions for their potential to suppress red rot under three different delivery systems, viz. sett treatment, soil application and their combination. All Trichoderma treatments resulted in considerable reduction in red rot (29.5–56.3%) over untreated control. However, the level of reduction accorded was much higher when the Trichoderma isolates were applied as a combination of sett and soil treatment (> 53% reduction) as compared to soil application (43–49% reduction) or sett treatment alone (< 35% reduction). Delivery of Trichoderma isolates as a combination of sett and soil treatment also exhibited highest NMCs and yield over untreated control. The application methods of talc formulations of these two isolates offer a feasible and effective option for large-scale application of these isolates for the management of red rot disease in sugarcane growing regions.

Assessment of Sugarcane Germplasm ( Saccharum spp. complex) Against Red Rot Pathogen Colletotrichum Falcatum

ABSTRACT Red rot, caused by Colletotrichum falcatum Went is the most important disease of sugarcane in India inflicting substantial loss to both cane industry and cane growers. To keep in view the importance of red rot disease of sugarcane, 117 accession of sugarcane germplasm including different Saccharum species and Indian and foreign commercial hybrids were tested against red rot with Cf 07, Cf 08 & Cf 09 (national pathotypes) by plug method of inoculation. Out of 117, 6 were found resistant and 12 were moderately resistant against red rot and rest were moderately susceptible/susceptible/highly susceptible. Theses resistance and moderately resistant accession can be further utilize to produce resistance varieties against the most devastating pathogen of sugarcane.

Molecular Characterization of Pathogenicity Gene Homologs in Colletotrichum falcatum Causing Red Rot in Sugarcane

Variation in Colletotrichum falcatum causing red rot disease of sugarcane is well established at cultural, pathogenic and molecular level. However, limited information is available on genes responsible for pathogen virulence and its pathogenesis. To understand virulence in C. falcatum, detailed studies were taken up using phylogenetically differentiated two isolates viz., Cf671 and Cf92020 vary in their virulence with 28 pathogenicity gene homologs. Important pathogenicity gene homologs amplified were PKS1, SCD1, THR1, Cap5, Cap20, MAF1, Pg1, PG2, Pel1, Pel2, SSD1, APH1, ArpA, ICL1, RGT2, RAC1, CreA, HXT1 and HXT3. Characterization of gene sequences of the selected pathogenicity genes from C. falcatum revealed both intra- and interspecific variation and comparison of genomic sources sequenced among two distinct isolates revealed a definite role of pathogenicity genes in C. falcatum pathogenesis. Differential expression of the pathogenicity gene homologs between isolates has been validated during host pathogen interaction.The present investigation identified the role of pathogenicity genes and their differential expression in C. falcatum pathogenesis for the first time.

Morphological, Cultural and Physiological Variations among Isolates of Colletotrichum Falcatum went That Cause Red Rot Disease of Sugarcane

Sugarcane is an important economical cash crop grown over an area of about 5.07 Mha in India. Red rot disease caused by the fungus Colletotrichum falcatum Went., is the most important and the dreaded disease affecting adversely the production of millable canes in India. Five isolates of C. falcatum were procured from ISSR, Lucknow; the culture was maintained on slants and Petri plates at 29°C. Variation in the cultural, morphological and physiological characteristics among the 5 isolates was investigated. These isolates were morphologically differentiated into two distinct groups: light colour and dark colour types based on the colony colour character. Three isolates (RR-08, RR-02 and RR-07) in the dark type produced gray colour colonies whereas isolates Cf-09 and Cf-08 in the light type had white colour colonies. The growth rate among all isolates varied from 10.6 to 11.9 mm.d-1 and was not significantly different. The five isolates produced setae and conidia that were hyaline, one-celled, falcate or sickle-shaped. The conidia of all isolates ranged between 31.2 and 36.5 μm in length and from 10.1 and 11.2 μm μm in width. All isolates were varied in their physiological characteristics. The optimum physical parameters for mycelial growth of the five strains was found to be 30°C for temperature, 5.5 (for four isolates viz., Cf-09, Cf-08, RR-08, RR-07) and 6.0 (for isolate RR-02) for pH. Host extract media maintained the highest mycelial growth in all the five isolates followed by PD broth. Dextrose and potassium nitrate were found to the best sources of carbon and nitrogen, respectively for maximum mycelial growth of Cf-09, Cf-08, RR-08 and RR-02 isolates while glucose and sodium nitrate were the best source of carbon and nitrogen, respectively for RR-07 isolate of C. falcatum. We have found that Colletotrichum falcatum isolates were culturally, morphologically and physiologically dissimilar.

Antifungal properties of rhamnolipid produced by Pseudomonas aeruginosa DS9 against Colletotrichum falcatum.

The rhamnolipid biosurfactant (RL-DS9) extracted from the bacterial strain Pseudomonas aeruginosa DS9 was evaluated for its antifungal activity against Colletotrichum falcatum that causes red rot in sugarcane. The surface tension (ST) reduction, biosurfactant production, and antifungal activity of biosurfactant against C. falcatum were investigated by using the medium with different carbon sources and it was found to be maximum in glucose. Moreover, highest reduction of ST and production of biosurfactant was achieved at 4.5% (w/v) concentration of glucose. The efficacy of RL-DS9 was compared with a commercially available rhamnolipid (RL-R95) using microtitre plate assay. Results showed that at 100 μg ml(-1) concentration RL-DS9 exhibited 86.6% inhibition against C. falcatum spore germination, and in the same concentration RL-R95 showed 83.3% inhibition. From liquid chromatography-mass spectrometry (LC-MS) analysis, it was revealed that only two similar congeners Rha-(C10 ) and Rha-Rha-(C10:1 ) were found to be in common among both the rhamnolipids. In the plant bioassay test, it was noted that red rot incidence was reduced on the sugarcane plants treated with RL-DS9. This is the first report that rhamnolipid biosurfactant produced by Pseudomonas aeruginosa DS9 could be able to control red rot disease of sugarcane caused due to the infection with the fungus Colletotrichum falcatum.

Suppression of red rot disease by Bacillus sp. based biopesticide formulated in non-sterilized sugarcane filter cake

Red rot disease affects sugarcane production adversely throughout the world. Intensive cropping and uninterrupted use of chemicals results in evolution of new pathotypes which can infect the resistant cultivars. Bacillus sp. inhabiting plant rhizosphere can protect the plants from multiple pathogens. In the present study, two antagonistic strains Bacillus subtilis NH-100 and Bacillus sp. NH-217 were able to maintain their population at 9.0 log CFU g−1 in sugarcane filter cake until nine months. These strains were compatibile to the indigenous bacteria of sugarcane filter cake which maintained their population at 7.8–8.0 log CFU g−1. The developed bioformulation induced the activity of various defense-related enzymes (0.6–6.9 change in absorbance min−1 g−1 of tissue), suppressed the red rot disease and enhanced crop yield under field conditions. This formulation could be used as potential biopesticide to control red rot disease of sugarcane.

Molecular profiling of systemic acquired resistance (SAR)-responsive transcripts in sugarcane challenged with Colletotrichum falcatum.

Red rot disease of sugarcane caused by Colletotrichum falcatum is one of the serious constraints affecting the productivity of the crop. The strategy of employing systemic acquired resistance (SAR) against red rot yielded consistently good results at field level. However, elucidation of genes involved in the induction of SAR continues to be a challenging area of research for a critical understanding of red rot disease resistance in sugarcane. Here, temporal expression of 22 putative defense-related genes were analyzed by semiquantitative reverse transcription-PCR (RT-PCR) in red rot-susceptible cultivar (CoC 671) with response to priming using various SAR inducers, viz. benzothiadiazole (BTH), salicylic acid (SA), and C. falcatum elicitor. Among the 22 genes studied, 12 transcripts were found to be differentially expressed, of which seven transcripts represent phenylpropanoid pathway and five transcripts represent resistant gene analogues (RGAs). Differentially regulated phenylpropanoid pathway genes such as cinnamic acid 4-hydroxylase, 4-coumarate:coenzyme A ligase, chalcone synthase, and chalcone reductase were reported to play a major role in the regulation of phytoalexin synthesis, whereas R genes such as NBS-LRR genes and basal layer antifungal peptide (BAF) genes were upregulated upon SAR induction in response to pathogen challenge. These upregulated genes presumably play a potential role in SAR induction and might contribute to defense against C. falcatum.

Role of Endochitinase Gene and Efficacy of Trichoderma Against Colletotrichum falcatum Went. Causing Red Rot Disease in Sugarcane

Role of endochitinase (ech42) gene in Trichoderma was worked out to prove the efficacy against most dreaded red rot disease of sugarcane caused by Colletotrichumfalcatum Went. Trichoderma spp. along with Trichoderma harzianum strain and Aspergillusawamori were tested against the virulent pathotypes of C. falcatum (Cf08, Cf09 and Cf401) under in vitro and in vivo conditions. T. harzianum was significantly able to control the incidence of red rot disease in highly susceptible sugarcane cultivar. PCR-Random amplified polymorphic DNA amplification results clearly separated T. harzianum 1, 2 and 3 from rest of the biological agents. T. harzianum 1 strain was highly diverse and making distant relationship with rest of the T. harzianum bioagents. Wide genetic distance was observed among the red rot pathogens and biological agents. The ech42 specific primers pair amplified a corresponding fragment of 1.5 kb in all Trichoderma spp. Thus, the presence of the ech42 gene was found to be correlated with the biocontrol activity of Trichoderma species. These findings clearly supported that ech42 gene is more specifically responsible for controlling the red rot incidence in sugarcane.

Expression profiling of transcription factors (TFs) in sugarcane X Colletotrichum falcatum interaction

Sugarcane is one of the most important commercial crops in India, supporting the second largest agro-based sugar industry. However for more than a century, the production is imperiled by the most devastating fungus Colletotrichum falcatum Went, which causes red rot in sugarcane. Complex polyploidy and limited understanding on the inheritance to red rot resistance makes breeding efforts more complicated in sugarcane. Transcription factors (TFs) play a key role in regulating defense response, which offers much promise for the manipulation of metabolic pathways, potential in regulating multiple signaling networks leading to plant defense against pathogens. In order to better manage red rot disease in sugarcane, we sought to screen the TFs possibly involving in pathogen defense by analyzing 5 major defense-related TF classes (WRKY, bZIP, MYB, NAC and TLP). In this study two parallel sets of experiments were carried out to compare the differential regulation of these classes of TFs upon pathogen challenge and SAR priming. Among the 41 TFs studied, differential regulation of 24 TFs upon pathogen challenge and 15 TFs upon SAR inducer priming were observed. Comparison of incompatible interaction and SAR inducer priming revealed that 8 TFs were highly induced in both the cases. Collectively, the results showed that TFs which are significantly induced early may involve actively in triggering or co-ordinating defense against pathogen invasion.

Detection of Colletotrichum falcatum causing red rot of sugarcane by enzyme-linked immunosorbent assay

Red rot disease of sugarcane caused by Colletotrichum falcatum Went is one of the most destructive diseases of sugarcane (Saccharum officinarum L.) worldwide. The pathogen spreads primarily through infected sugarcane setts and hence the use of disease-free setts is essential to prevent the disease. In order to develop immunological method for detection of C. falcatum, two proteins with molecular weights of 27 kDa and 45 kDa were purified from the mycelium of C. falcatum race Cf 05 and used as antigen source to raise polyclonal antibodies in NewZealand white rabbit. The developed polyclonal antibodies were tested for detection of C. falcatum by enzyme-linked immunosorbent assay (ELISA) and immunoblot analysis. The polyclonal antibodies specifically detected C. falcatum in extracts from infected plants, both in immunoblot and ELISA. The ELISA results showed that the developed polyclonal antibodies were highly specific to C.falcatum. The developed antibodies were very sensitive and could detect C.falcatum proteins even at a dilution of 1:50,000. Higher ELISA absorbance values were recorded even at an antigen dilution of 1:500. In western blot analysis, protein bands with molecular weights of 27 kDa and 45 kDa reacting to antisera raised against 27 kDa and 45 kDa mycelial proteins of C. falcatum, respectively, were detected in protein samples from red rot infected canes. The high specific reactivity and sensitivity of the antisera indicate its potential suitability for ELISA-based detection of C. falcatum.