Vol. 125 (2012): Proceedings of the Florida State Horticultural Society
Citrus

Responses of Citrus medica var. sarcodactylisduring Xanthomonas citrisubsp. citriInfection

Naveen Kumar
Southwest Florida Research and Education Center, University of Florida, IFAS, Immokalee, FL 34142
Robert C Ebel
Southwest Florida Research and Education Center, University of Florida, IFAS, Immokalee, FL 34142
Pamela D Roberts
Southwest Florida Research and Education Center, University of Florida, IFAS, Immokalee, FL 34142

Published 2012-12-01

Keywords

  • Citrus medica,
  • catalase,
  • peroxidase,
  • reactive oxygen species

Abstract

Asiatic citrus canker [Xanthomonas citri subsp. citri; (Xcc)] is a serious bacterial disease that can causes economic losses in citrus production and marketing throughout the world. In the present investigation, canker lesion development was examined in Buddha Hand (Citrus medicavar. sarcodactylis), which is an ornamental tree. Basal matured leaves (fully expanded) were inoculated using a tuberculin syringe (1 cc) without a needle. Citrus canker inoculum (1.1 × 10
6cfu/cm2) was slowly infiltrated into the abaxial leaf surface on both sides of the mid vein to produce a zone of water-soaked tissue. The highest Xccpopulation (1.9 × 1011cfu/cm2 ) was observed at 8 days after inoculation (dai) and thereafter declined. This decline was associated with higher oxidative redox of host tissue. These results showed that Buddha Hand represents a delayed type of hypersensitive-like response. Buddha Hand may serve as an important citrus species for resistance to citrus canker that might be exploited through transgenic and hybrid plants.