Phenotypic and genotypic diversity of Puccinia kuehnii, causal agent of orange rust, at a sugarcane breeding site

• Grant number: 17/14351-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2017
• End date: December 31, 2018
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Alfredo Seiiti Urashima
• Grantee: Lis Natali Rodrigues Porto
• Host Institution: Centro de Ciências Agrárias (CCA). Universidade Federal de São Carlos (UFSCAR). Araras , SP, Brazil
• Associated scholarship(s): 17/25455-1 - Development of molecular markers to identify different physiologic races of Puccinia kuehnii, the causal agent of orange rust of sugarcane, BE.EP.IC

Abstract

The orange rust, caused by Puccinia kuehnii, is one major disease of sugarcane industry due to yield loss and economic impact, as observed in Australia. Soon after the disease reached Brazil in 2009 three varieties were identified as highly susceptible, abolished and replaced by resistant varieties. The use of resistant genotypes has been the ideal method to cope with this disease in every sugarcane growing countries of the world. This strategy proved effective in Australia when replacement of Q124 made orange rust a minor disease, as it was before 2000. Hence, the sugarcane industry in Brazil was taken aback when orange rust epidemics occurred in 2012-13 in SP81-3250 and CTC15, varieties not included as susceptible before. One cause of such event may be explained by the high pathogen diversity. Therefore, it is essential that varieties be challenged against all pathogen variant before release. One of the first steps towards this goal is to know the diversity at a sugarcane breeding site, and due to the huge amount of materials to be challenged, this process is done by exposing materials to natural inoculation. In this process, a phenomenum known as cryptographic error can occur, where breeding lines were not challenged against low frequency strains of the pathogen due to multipustule nature of the natural infection and thus, masking the true pathogen diversity. The objective of the present work aims to overcome this situation by employing single pustule inoculation to examine phenotypic and genotypic diversity of P. kuehnii at a sugarcane breeding center. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

PORTO, L.; ARIAS, R. S.; SEIITI URASHIMA, A.. Single-pustule inoculation to examine diversity of the Brazilian orange rust pathogen from various origins and uredia. PHYTOPATHOLOGY, v. 108, n. 10, p. 1-pg., 2018-10-01. (17/14351-0)

ECKER, G.; PORTO, L.; ARIAS, R. S.; CANO, L. M.; ROTT, P. C.; URASHIMA, A. SEIITI. Sugarcane cultivars susceptible to orange rust can host sub-populations of Puccinia kuehnii capable of infecting resistant cultivars. PHYTOPATHOLOGY, v. 109, n. 10, p. 1-pg., 2019-10-01. (17/14351-0)

URASHIMA, ALFREDO SEIITI; MISTURA, TATIANE DE FATIMA; RODRIGUES PORTO, LIS NATALI; AUSTIN, PAIGE DARIEL; ARIAS, RENEE SILVIA. Genetic diversity ofPuccinia kuehnii, the causal agent of orange rust of sugarcane, from Brazil. JOURNAL OF PHYTOPATHOLOGY, v. 168, n. 10, AUG 2020. (17/14351-0)