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3/8/11
1
Recent changes in cotton leaf curl disease complexes; are we heading
Towards another epidemic?
Dr. Shahid Mansoor, S.I
Agricultural Biotechnology Division,
National Institute for Biotechnology and Genetic
Engineering (NIBGE), Faisalabad, Pakistan
Cotton leaf curl virus has great impact on economy Ø Pakistan loses 3 million bales (Equivalent to Rs. 120 billion per year) Ø Other losses are seed, oil, seedcake Ø Net importer of cotton
Geminivirues are a global threat • Cassava mosaic disease in Africa • Cotton leaf curl in Pakistan • Beans in India and South America
Geminiviridae
• Mastrevirus • Curtovirus • Topocuvirus • Begomovirus
MP
CP
RepA
RepB
C4
V2 MP
C2 REn Rep
CP
C4
Rep C2
C3
V2
DNA B
MP NSP
DNA A
V2
C4
Rep TrAP REn
CP
CP
Cotton leaf curl virus epidemic in Pakistan Epidemic level in 1992 Heavy losses to Pakistan cotton (5 billion US dollars)
Virus impact
Begomoviruses known before
Begomoviruses discovered by us
Begomovirus species associated with cotton leaf curl disease Cotton leaf curl Multan virus Cotton leaf curl Alaabad virus Cotton leaf curl Khokhran virus Cotton leaf curl Rajasthan virus Sequence analysis suggest that some of these are recombinants
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Distinct begomoviruses associated With Cotton leaf curl disease interact with cotton beta
C1 GENE A-RICH SCR
Geminivirus disease complexes on cotton
Begomovirus disease complex Monopartite begomoviruses with satellites Common in Asia/Africa Bipartite begomoviruses Found in Americas
Phylogenetic relationships of cotton begomoviruses
New World
Africa
Asia
What we learned? DNA beta interacts with distinct begomoviruses and mobilize them in cotton How quickly it is happening? What are the consequences?
How quickly geminivirus disease complexes are evolving ????
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How quickly? New species associated with the disease Papaya leaf curl virus Tomato leaf curl Karnataka virus Experimental interaction Ageratum yellow vein virus Singapore Tomato leaf curl virus Australia Consequences? Resistance breakdown? Changes in host range?
The spread of Burewala virus 2001-2003
The spread of cotton leaf curl virus (1991-1996)
Breakdown of resistance in cotton
The spread of Burewala virus 2001-2008
The spread of cotton leaf curl virus (1991-1996)
Breakdown of resistance in cotton DNA A
V2
C4
Rep TrAP
REn
Cotton leaf curl Kokhran virus
CP
DNA A
V2
C4
Rep TrAP
REn
Cotton leaf curl Multan virus
CP
DNA A
V2
C4
Rep
REn TrAP
CP
Cotton leaf curl Burewala virus
Burewala strain 2001-2008
Conclusions ü Geminivirus disease complexes are evolving rapidly
ü Pose a serious threat to world agriculture
Why? International trade TYLCV from Israel to North America SqLCV from North America to Israel Cotton beta can interact with local viruses Bioterrorism?
Serious threat to world agriculture
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Who is at risk? Where whiteflies have established as pest Indian subcontinent Australia China Americas Southern Europe
Viruses in Sindh 2009-2010
Cotton leaf curl complexes in Sindh Cotton leaf curl Shahdadpur virus Along with Cotton leaf Shahdadpur alphasatellite Cotton leaf curl Multan betasatellite But the most strange is
Cotton leaf curl Gezira virus
Related to CLCuGV from Egypt
CLCuGV is found with Multan betasatellite and Chilli leaf curl betasatellite
CLCuGV interacts with both betasatellites from Pakistan
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Possible land and sea routes for introduction 2009-2010 A new complex
emerging in Punjab??
Changes in the complex in Punjab Presence of alphasatellites in Punjab Presence of chilli betasatellite in cotton sample along with cotton betasatellites Is it a synergism involving satellites?
Take home message • Cotton leaf curl complex is adopting rapidly (against resistance) • Require broad-spectrum resistance • Gene pyramiding for durable solution § Team effort will win against this menace