Many thanks for the emails re the CICYL group, and for putting me on the list. This is particularly helpful and timely as I am currently putting together a full application for BBSRC/DFID funding to carry out some further work on seed transmission of LY and also sustainable breeding of tolerant / resistant varieties in Africa, based on an ongoing collaboration with CSIR-OPRI in Ghana. This was following approval of a concept note that I put in before Christmas.
I was therefore wondering whether you could provide me with a bit of further help toward this proposal, particularly on the resistance in coconuts side, as one of the aims is to try and improve our understanding of the genetics of resistance and develop some tools for marker assisted breeding.
As I understand it, resistance to LY in Jamaica is believed to be controlled by a single major co-dominant gene locus with the influence of minor modifier loci, whilst in Tanzania there are two or more partially dominant genes involved. Is this still the case, and in these breeding programmes were F2's produced and any work done on confirming the heritability? I know there was some attempt to develop RAPD markers associated with resistance (Cardena et al 2003) but this was done using palms that had been exposed to LY and had survived as the resistant material.
My colleague in Ghana has produced WAT / SGD and WAT / VTT hybrids that are resistant / tolerant, and we are proposing to take these to F2, and at least look at the segregation of molecular markers in them although there will not be time within the project to look at their resistance/susceptibility to disease, so we will also be using a similar approach to Cardena to find linked markers.
Look forward to hearing from you
According to Simon Eden-Green "Recent progress in immunological
methods for the detection of phytoplasmas is likely to lead to
practical techniques for the diagnosis of coconut palms in early,
probably pre-symptomatic, stages of disease. Subject to suitably low
production costs, this could be used to improve the efficiency of
large-scale LYD surveillance and control operations. This is based on
the ability to clone a dominant phytoplasma membrane protein gene,
secA, into a bacterial expression system and to produce anti-secA
antibodies that can be used in a simple enzyme-linked immunological
assay such as a membrane-based lateral flow device. A research group
led by Dr Matt Dickinson at the University of Nottingham, UK, working
with researchers from the UK Central Science Laboratory, from Ghana,
and Dr Nigel Harrison in Florida, has amplified part of the secA gene
from coconut LYD phytoplasmas from Tanzania, Ghana and Mexico. The
resultant PCR products have been cloned, sequenced and confirmed to be
secA. These sequences are currently being cloned into an E.coli
expression vector, and the expressed protein will then be purified and
used to produce anti-secA antibodies for LYD phytoplasmas. The
antibodies will then be evaluated on samples obtained from Ghana to
confirm their ability to detect phytoplasma in vivo. It is thought
that this work could be extended and practical techniques developed
within a 12-18 month timescale for use in Mozambique and elsewhere,
subject to availability of further funding, some of which may come
from a new UK Biology and Biotechnology Science Research Council
scheme operating with the UK Department for International Development".
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