Relationships of the Sardinian isolate of tomato yellow leaf curl geminivirus with its whitefly vectorBemisia tabaci Gen

Abstract

Relationships of an Italian isolate of tomato yellow leaf curl geminivirus from Sardinia (TYLCV-S) with its whitefly vector Bemisia tabaci were studied by means of experimental transmissions from tomato to tomato plants. TYLCV-S was confirmed to be transmitted in a persistent, circulative manner. The minimum latent period in the vector was between 17 and 20 h from the beginning of the acquisition access period (AAP). The maximum retention of infectivity was 8 days from the end of the AAP. Both acquisition and inoculation feeding times influenced the detected proportion of infective insects, with patterns well described by an exponential model. Acquisition was more efficient than inoculation. Males were significantly less efficient vectors than females. Nymphs were as efficient as adults in acquiring the virus. The length of AAP influenced both the retention of infectivity, and the pattern of transmission in serial transfer transmission tests with individual females. No significant difference in transmission efficiency was detected between two colonies of B. tabaci, one inducing typical silverleaf symptoms on squash, the other inducing only mild symptoms with more than 50 whiteflies per plant. The phenomenon of periodic acquisition was not unequivocally proved for TYLCV-S.

Virion Stability Is Important for the Circulative Transmission of Tomato Yellow Leaf Curl Sardinia Virus by Bemisia tabaci , but Virion Access to Salivary Glands Does Not Guarantee Transmissibility

“…6A). In the control, transmission efficiency of the wt virus fell within the expected values for a 12-h AAP (17). No inhibition was observed with the PNHD mutant.…”

“…The main parameters governing acquisition and transmission of TYLCSV and the related species TYLCV are already known (17,19,20). The kinetic experiments reported here showed that the infectious and virion-forming NT mutants PNHD and PNHE, or at least their DNA, persisted in whiteflies as the wt virus did, indicating that they circulated in B. tabaci hemocoel and reached the head/prothorax organs.…”

“…B. tabaci whiteflies, biotype B, originating from Liguria, Italy, were raised on TYLCSV-immune cucumber plants (Cucumis sativus L.; cv. Marketer), in a quarantined room at 26°C Ϯ 1°C, under a 16:8 h (light-dark) photoperiod (17). Trialeurodes vaporariorum Westwood insects were reared on N. tabacum L. plants (cv.…”

The Transmission Efficiency of Tomato Yellow Leaf Curl Virus by the Whitefly Bemisia tabaci Is Correlated with the Presence of a Specific Symbiotic Bacterium Species

“…While acquisition and transmission of TYLCV by B. tabaci have been studied in some detail (6,7,30,36), the molecular interactions between this geminivirus (as well as others) and its insect vector are still poorly understood. Similar to other whiteflyborne geminiviruses, B. tabaci transmits TYLCV in a persistent-circulative nonpropagative manner (15), while some evidence points to viral transcriptional activity in the vector (38).…”

Short communication. Effect of Bemisia tabaci biotype in the transmission of Tomato Yellow Leaf Curl Sardinia Virus (TYLCSV-ES) between tomato and common weeds

“…Whether this is because the different biotypes feed more voraciously on one plant than on another or whether they feed in different locations on or within the leaf (affecting virion acquisition), will require a further investigation. A difference in the transmission efficiency of TYLCV by B. tabaci biotypes has also been reported by Caciagli et al (1995) and McGrath and Harrison (1995). The reproductive activity of B and Q-biotypes of B. tabaci was shown to differ , and studies using the electrical penetration graph technique (EPG) on stylet penetration in relation to probing and feeding behaviour (Jiang et al, 2001) of these two B. tabaci biotypes also showed differences.…”