By Lara Ivanitch
Spoorti Gandhadmath carefully placed 3.5-inch pots on a shelf in a growth chamber. Within seven days of sowing, newly sprouted leaves had fully emerged from each of the carefully selected seeds, representing diverse cotton genotypes.
Gandhadmath, a doctoral student in crop science at NC State University, then inoculated the seedlings with race 18 of the cotton bacterial blight pathogen as part of her work in the Kuraparthy Lab. Seven days after that, she checked the tiny leaves for water-soaked spots that indicated infection, or dry, dead patches that revealed the plant had resistance to this particularly virulent strain of blight.
Known as phenotyping, Gandhadmath tracked the plants’ observable responses to the bacterium as the first step in a study recently published in The Plant Genome. This study explored the genetic makeup of cotton plants in search of the source of their resistance to bacterial leaf blight, which has reemerged as a threat to cotton production in the United States.
“Our team was surprised by what we found,” Gandhadmath says. “The cotton lines we studied showed strong resistance to the aggressive race 18 of the disease.”
A Growing Concern
Cotton bacterial blight, also known as angular leaf spot, begins as small, dark green, water-soaked spots on the undersides of cotton leaves. As the spots grow, leaf veins restrict their spread, giving them an angular shape. Larger lesions appear on both sides of leaves, develop reddish-brown borders and can spread along major veins.
The disease thrives in warm, humid, rainy conditions and can affect cotton throughout its life cycle, from germination to harvest. It attacks all parts of the plant, including seeds, stems and bolls, causing premature defoliation, lint discoloration and seed rot.
Source : ncsu.edu