Transmission of Acidovorax avenae subsp. avenae, the causal agent of red stripe disease in Sugarcane

MONACHESI MA; BERTANI RP; GONZÁLEZ V; ARIAS ME

Congreso; XXXI ISSCT Congress; 2023

International Society of Sugar Cane Technologists

Red stripe disease of sugarcane [Acidovorax avenae subsp. avenae (Aaa)] is characterized by two symptoms: leaf stripe and top rot. At present, knowledge on sugarcane colonization by Aaais limited. For this reason, the aim of this work was to evaluate the transmission of Aaa by sugarcane infected leaves and stalks. TUC 00-19 variety (susceptible to red stripe) was used in the assays. Treatments consisted of single buds obtained from stalks with leaf stripe and top rot symptoms, planted in sterile soil. Additionally, healthy single-buds planted in sterile soil mixed with red stripe-leaves collected at different times before planting were included. Shoot emergence and symptom expression were recorded. The presence of Aaa in sugarcane leaves was determined by isolation and their identity was confirmed by PCR. Shoot emergence wasgreater than 80% in all treatments; plant emergence from buds obtained from cane with top rot symptoms was not affected, probably because of the previous removal of the stem-rot portion. Only four out of five treatments from the mixture of sterile soil and red stripe-leaves exhibited typical symptoms. Five out of 152 isolates were positive by PCR; four of them corresponded to asymptomatic plants. This study gives a better understanding of the life cycle of this pathogen and, therefore, informs appropriate management strategies to control the disease in commercial fields.