Skip to main content
ARS Home » Research » Publications at this Location » Publication #138018
Title: TRANSMISSION OF XYLELLA FASTIDIOSA TO SWEET ORANGE SEEDLINGS BY CONTAMINATED SEEDS

Author
item LI, WENBIN - 1275-11-00
item W.D, PRIA - UNIVERSITY OF SAO PAULO
item PM, LACAVA - UNIVERSITY OF TAWBATE
item Hartung, John

Submitted to: Plant Pathology International Congress
Publication Type: Abstract Only
Publication Acceptance Date: 10/15/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Xylella fastidiosa, causes citrus variegated chlorosis, an important disease of citrus in South America. The pathogen is transmitted by sharpshooter insects and budwood. X. fastidiosa extensively colonizes the xylem vessels of susceptible plants, but the presence of the bacterium in fruit and seed has not been studied. Citrus fruit and seed have a well developed vascular system, which is continuous with the vascular system of the plant. Symptomatic and asymptomatic sweet orange fruit of cultivars "Pera", "Valencia" and "Natal", were collected and analyzed for the presence of X. fastidiosa by PCR. X. fastidiosa was detected in all main fruit vascular bundles, and also in both the inner and outer seed coats, and the embryos of seeds. The identification of X. fastidiosa in the infected seeds was confirmed by cloning and sequencing the specific amplification product. X. fastidiosa was also detected in and recovered from seedlings by isolation in vitro. No visual abnormalities were observed in seeds infected with the bacterium. However, the embryos of the infected seeds weighed 25% less than healthy embryos, and the germination rate of infected seed was 10% less than uninfected seed. X. fastidiosa was not detected in asymptomatic sweet orange fruit or seed collected from such fruit. There were about 2500 cells of X. fastidiosa per infected seed of sweet orange, as quantified using Real-Time quantitative PCR techniques. Our results show that X. fastidiosa can infect and colonize fruit tissues including the seed, and X. fastidiosa can be transmitted from seeds to seedlings of sweet orange.