Construction of agro-infectious clones and screening of tomato cultivars for tolerance against tomato leaf curl Sudan virus and tomato yellow leaf curl virus.
Mahmoud Ahmed Amer1*, Zaheer Khalid1, Khadim Hussain1, Muhammad Amir1, Muhammad Zaman1, Ibrahim Mohammed Al-Shahwan1, Mohammed Ali Al-Saleh2*
1Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
2Chair of Date Palm Research, Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
Abstract
Tomato leaf curl disease is the most harmful disease of tomato caused by different begomovirus species mainly Tomato yellow leaf curl virus (TYLCV) and Tomato leaf curl Sudan virus (TLCSDV). Both are single-stranded DNA begomoviruses that cause leaf curling, stunting, vein banding, yellowing and results in significant crop losses in tomato in Saudi Arabia. In the first objective of this study, infectious clones of TLCSDV and TYLCV were constructed by cloning and subcloning of partial dimer genome containing two origins of replication on PstI-KpnI/KpnI sites in binary plasmid vector pGreenII 0000. To assess the functionality of agro-infectious clones, those were transformed into Agrobacterium tumefaciens GV3101 strain and infiltrated into the leaves of model host plant Nicotiana benthamiana. Three weeks post inoculation begomovirus symptoms were observed and infectivity of our infectious clones were confirmed by PCR using begomovirus diagnostic primers (AC1048 and AV494). In the second phase, 13 available commercial cultivars of tomato crop grown in open fields as well as greenhouse were inoculated with agro-infectious clones of TLCSDV and TYLCV to assess their tolerance against these important pathogens of tomato. The obtained results observed after 30 days of inoculation showed all cultivars were susceptible to both begomoviruses showing variable symptoms severity. These results were confirmed by PCR using AC1048 and AV494 primer. The significance of response of different cultivars against infection of TLCSDV and TYLCV were discussed.
