Endophytic Colletotrichum siamense for Biocontrol and Resistance Induction in Guarana Seedlings.

Luana L Casas,Lucas N Almeida,João L Azevedo,Roberto A Bianco,José O Pereira,José F Silva,Pedro Q Costa-Neto,Clemencia Chaves Lopez

doi:10.1155/2021/1925226

Abstract

Paullinia cupana var. sorbilis, known in Brazil as guarana plant, is an important plant and a major traditional crop in the State of Amazonas. It is a native Brazilian species of great economic and social importance, particularly in the Amazon region. Anthracnose caused by Colletotrichum spp. is the main challenge for this crop. Therefore, the present study verified whether C. siamense, an endophytic fungus infected with a mycovirus, could protect the seedlings and reduce or eliminate the characteristic symptoms. Total proteins and enzymatic activities of pathogenesis-related proteins (PRPs), including peroxidase (POX), chitinase (CHI), and phenylalanine ammonia lyase (PAL), were quantified. Guarana seedlings of cultivar Maués were sprayed with a C. siamense conidia suspension (5.0 × 103 conidia/mL). After ten days, the seedlings were sprayed with a suspension of the phytopathogen's conidia (1.0 × 106 conidia/mL). One group of these seedlings received the fungicide indicated for this crop. The fungicide was applied twice with an interval of 15 days between applications. Negative control seedlings did not receive any treatment (except water and fertilization), and positive control seedlings were treated only with the phytopathogen. The experiment was conducted between December 2019 and February 2020 in a greenhouse. The treatments were applied at an average temperature of 25°C and 85% relative humidity. Leaflets were randomly collected from each treatment group at 0, 48, 72, and 96 hours after pathogen inoculation and analyzed for total protein and enzyme production (POX, PAL, and CHI). After 28 days, the percentage of leaf lesions on the seedlings was evaluated. C. siamense inoculation reduced lesions. There were differences in total proteins and PRPs at different timepoints after inoculation, except for CHI activity, among treatments. To the best of our knowledge, this is the first record of resistance induction in guarana plants.

Highlights

Paullinia cupana var. sorbilis, known in Brazil as guarana plant, is an important plant and a major traditional crop in the State of Amazonas
Anthracnose caused by Colletotrichum spp. is the main challenge for this crop. erefore, the present study verified whether C. siamense, an endophytic fungus infected with a mycovirus, could protect the seedlings and reduce or eliminate the characteristic symptoms
The present study evaluated whether the endophytic fungus C. siamense induced resistance and reduced or eliminated typical symptoms in guarana seedlings of the BRS-Maues clone

Summary

Introduction

Paullinia cupana var. sorbilis, known in Brazil as guarana plant, is an important plant and a major traditional crop in the State of Amazonas. Sorbilis, known in Brazil as guarana plant, is an important plant and a major traditional crop in the State of Amazonas. It is a native Brazilian species of great economic and social importance, in the Amazon region. Guarana seedlings of cultivar Maues were sprayed with a C. siamense conidia suspension (5.0 × 103 conidia/mL). The seedlings were sprayed with a suspension of the phytopathogen’s conidia (1.0 × 106 conidia/mL). One group of these seedlings received the fungicide indicated for this crop. Colletotrichum spp. cause anthracnose in guarana plants, characterized by leaf blight followed by defoliation. Physiological interactions between plants and microorganisms (fungi and bacteria) may bring benefits to agriculture, as these interactions promote plant growth and resistance [8]

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Results

Conclusion