Rapid differentiation of graft Citrus sinensis with and without Xylella fastidiosa infection by mass spectrometry

Abstract

Rationale Xylella fastidiosa causes citrus variegated chlorosis (CVC) in sweet orange trees. A diagnostic method for detecting CVC before the symptoms appear, which would inform citrus producers in advance about when the plant should be removed from the orchard, is essential for reducing pesticide application costs. Methods Chemometrics was applied to high‐performance liquid chromatography diode array detector (HPLC‐DAD) data to evaluate the similarities and differences between the chromatographic profiles. A liquid chromatography/atmospheric pressure chemical ionization mass spectrometry selected reaction monitoring (LC/APCI‐MS‐SRM) method was developed to identify the major compounds and to determine their amounts in all samples. Results We evaluated the effect of this bacterium on the variation in the chemical profile in citrus plants. The organs of C. sinensis grafted on C. limonia were analyzed. Chemometrics was applied to the obtained data, and two major groups were differentiated. Flavonoids were observed in one group (leaves) and coumarins in the second (roots), both at higher concentrations in the plants with CVC symptoms than in those without the symptoms and those in the negative control. The rootstocks also interfered in the metabolism of the scion. Conclusions The developed LC/APCI‐MS‐SRM method for detecting CVC before the symptoms appear is simple and accurate. It is inexpensive, and many samples can be screened per hour using 1 mg of leaves. Knowledge of the influence of the rootstock on the chemical profile of the graft is limited. This study demonstrates the effect of the rootstock in synthesizing flavonoids and increasing its content in all parts of the graft.

Secondary Metabolites in Xylella fastidiosa–Plant Interaction

“…Later on, the authors showed as, in Brazilian C. sinensis grafted on C. limonia cv. Pêra, the rootstocks interfere in the metabolism of the scion, determining a higher concentration of flavonoids (hesperidin) in leaves of symptomatic CVC-infected plants compared to asymptomatic and control plants, suggesting that the increase of this flavonoid can hence reduce the susceptibility of sweet orange to this bacterium [ 62 ].…”

Comparative metabolomics analysis of Citrus medica var. sarcodactylis Swingle and Limonia acidissima Linn. Fruits and leaves cultivated in Egypt in context to their antiviral effects

“…Peak 54 in Table 1 which represent 5,6,7,8,3′,4′-Hexamethoxy flavone(nobiletin) whose molecular weight in positive mode is (403) + peak 388 appear due to loss of methyl group (M + H–CH 3 ), peak 373 due to loss of CH 2 O group (M + H–CH 2 O), peak 211(RDA,ring A), peak 183(211-CO)and peak163 (RDA, ring B) [ 25 ] .…”

Safeguarding Citrus: Exploring State-of-the-art Management Strategies for Bacterial Citrus Diseases

“…The study analyzed samples of C. sinensis grafted on C. limonia, revealing elevated flavonoid concentrations in leaves and coumarins in roots of symptomatic plants compared to asymptomatic and healthy plants. Based on these findings, Soares et al suggested that the LC/APCI-MS-SRM method could effectively detect CVC before symptomatic manifestations, offering a simple and accurate diagnostic approach [96].…”