« Previous AbstractEvolution of Streptococcus pneumoniae and its close commensal relatives    Next AbstractAll roads lead to Rome: Towards understanding different avenues of tolerance to huanglongbing in citrus cultivars »

Plant Physiol Biochem

Title:		Metabolically speaking: Possible reasons behind the tolerance of 'Sugar Belle' mandarin hybrid to huanglongbing
Author(s):		Killiny N; Valim MF; Jones SE; Omar AA; Hijaz F; Gmitter FG; Grosser JW;
Address:		"Department of Plant Pathology, University of Florida, IFAS, CREC, 700 Experiment Station Rd, Lake Alfred, FL 33850, USA. Electronic address: nabilkilliny@ufl.edu. Department of Plant Pathology, University of Florida, IFAS, CREC, 700 Experiment Station Rd, Lake Alfred, FL 33850, USA. Horticultural Sciences Department, University of Florida, IFAS, CREC, 700 Experiment Station Rd, Lake Alfred, FL 33850, USA; Biochemistry Department, College of Agriculture, Zagazig University, Zagazig, 44511, Egypt. Horticultural Sciences Department, University of Florida, IFAS, CREC, 700 Experiment Station Rd, Lake Alfred, FL 33850, USA"
Journal Title:		Plant Physiol Biochem
Year:		2017
Volume:		20170504
Issue:
Page Number:		36 - 47
DOI:		10.1016/j.plaphy.2017.05.001
ISSN/ISBN:		1873-2690 (Electronic) 0981-9428 (Linking)
Abstract:		"Huanglongbing (HLB) is currently considered the most destructive disease of citrus. Since its spread to the Americas, HLB has killed millions of trees and caused a sharp decline in production in many citrus growing regions. With the continuous spread of HLB disease in Florida and worldwide, there is an urgent need for the development of commercial citrus cultivars with a strong tolerance to HLB. Interestingly, field observations showed that some of the recently released mandarin hybrids such as 'Sugar Belle' were tolerant to HLB. In this study, we investigated the volatile and non-volatile metabolites of greenhouse-grown 'Sugar Belle' mandarin and four of its ancestors in order to understand why 'Sugar Belle' mandarin is relatively tolerant to HLB. Leaf volatiles were directly extracted with hexane and analyzed using gas chromatography-mass spectrometry (GC-MS). Leaf polar metabolites were extracted with a mixture of methanol:water (1:1, v/v), derivatized to their trimethylsilyl ethers, and analyzed using GC-MS. Forty-seven volatile compounds and forty-two polar metabolites were detected in 'Sugar Belle' mandarin leaves and its ancestors. 'Sugar Belle' was high in several volatiles such as alpha-thujene, para-cymene, gamma-terpinene, thymol, beta-elemene, and (E)-beta-caryophyllene. Some of these volatiles, especially thymol, beta-elemene, and (E)-beta-caryophyllene are known for their anti-microbial activity. In addition, 'Sugar Belle' mandarin was the highest in synephrine, benzoic acid, ferulic acid, caffeic acid, chiro-inositol, fructose, glucose, threonic acid, saccharic acid, and galactaric acid, and the second in threonine, malic acid, and myo-inositol compared to the ancestors. Phenolic compounds such as benzoic, ferulic, and caffeic acids may act as antibacterial agents, whereas others like sugar alcohols may protect 'Sugar Belle' mandarin from stress during pathogen attack. The tolerance of 'Sugar Belle' and other newly released mandarin hybrids should be further evaluated using greenhouse controlled studies. If tolerance of these hybrids is confirmed, they could be used to replace the traditionally susceptible cultivars"
Keywords:		Bicyclic Monoterpenes Citrus/*metabolism Gas Chromatography-Mass Spectrometry Inositol/metabolism Monoterpenes/metabolism Plant Diseases/immunology/microbiology Plant Leaves/*metabolism Polycyclic Sesquiterpenes Sesquiterpenes/metabolism Sugar Acids/metab;
Notes:		"MedlineKilliny, Nabil Valim, Maria Filomena Jones, Shelley E Omar, Ahmad A Hijaz, Faraj Gmitter, Fred G Jr Grosser, Jude W eng France 2017/05/14 Plant Physiol Biochem. 2017 Jul; 116:36-47. doi: 10.1016/j.plaphy.2017.05.001. Epub 2017 May 4"