ARS | Publication request: The effects of ‘Candidatus Liberibacter asiaticus’ infection on the protein expression profiles and nutrient status of Citrus plants

Submitted to: Biochemistry and Molecular Biology Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 2, 2012
Publication Date: April 21, 2012
Citation: Nwugo, C.C., Lin, H., Duan, Y. 2012. The effects of ‘Candidatus Liberibacter asiaticus’ infection on the protein expression profiles and nutrient status of Citrus plants. Biochemistry and Molecular Biology Abstracts. p. 156.

Technical Abstract: Huanglongbing (HLB) is a destructive disease of citrus plants causing significant yield loss within 4-6 years of initial infection. The etiology of HLB worldwide is associated with three insect-transmissible phloem-limited members of the bacterial group ‘Candidatus Liberibacter spp’, prevalently ‘Candidatus. Liberibacter asiaticus’ (Las). In this study, two dimension polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry analyses were used to elucidate protein expression profiles in leaves of Las-infected grapefruit and lemon plants in presymptomatic and symptomatic stages of the disease. 2D-PAGE analysis detected over 200 and 70 protein spots that were differentially expressed in response to Las infection in grapefruit and lemon plants, respectively. Interestingly, matrix-assisted laser desorption/ionization-time of flight mass spectrometry analysis showed that chitinase and starch synthase are among a subset of proteins precociously induced in leaves of grapefruit plants infected by Las. To further investigate effects of the disease on nutritional status of plants, Inductively coupled plasma spectroscopy was employed to measure the major nutritional elements (Mg, Ca, K, Zn and Fe) in leaves and root tissues. Nutrient concentration analysis suggests that active accumulations of Zn in lemon and Ca in grapefruit leaves are associated with citrus response to Las infection. In summary, this study provides new information concerning physiological and biochemical responses of citrus to HLB, which will facilitate development of host-based biomarker(s) for early detection and improved nutritional management of the disease.