Browsing by Author "Nutt, KA"

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Canegrub resistant plants containing antimetabolic compounds : SRDC final report BSS163
(BSES, 2000) Smith, GR; Nutt, KA; Allsopp, PG
Transgenic sugarcane plants engineered to express either the potato proteinase inhibitor II or the snowdrop lectin gene show increased antibiosis to larvae of Antitrogus consanguineus in pot-based glasshouse trials.Canegrubs feeding on the transgenic line UP87, transformed with the potato gene, gained as little as 4.2% of the weight of canegrubs fed on untransformed control plants. Similarly, larvae feeding on the roots of transgenic line G87, transformed with the snowdrop gene, gained only 20.6% of the weight of grubs feeding on the non-transgenic control plants. Overall, 22% of the tested transgenic plant lines engineered with either the potato or the snowdrop constructs resulted in a statistically significant reduction in gain of weight by canegrubs feeding on roots. Weight gains of insects were compared to those of larvae feeding on the roots of either non-transgenic control plants, or non-transgenic plants regenerated after passage through the tissue culture system.Plants transformed with a proteinase inhibitor from an ornamental tobacco showed no statistical effect on the weight gain of the grubs. This result was unexpected, as the proteinase inhibitor from tobacco was predicted to be as effective as the PI from potato. Further analysis of the gene construct by sequencing established that the gene construct was faulty in contrast to the original restriction analysis that had indicated that the plasmid was correctly constructed. Protein could not be produced by the faulty construct, and this is reflected in the negligible effect on weight gain of the grubs. The plasmid was re-constructed and transformed into sugarcane. Plants containing this construct are being grown for testing.Having now established that canegrub resistance can be engineered into sugarcane, the next phase is to test the efficacy of these transgenes against other species of canegrub larvae and to further develop a commercial product.
Characterisation of proteinase inhibitors from canegrubs for possible application to genetically engineer pest-derived resistance into sugarcane : SRDC final report STU032
(2005) Nutt, KA
The primary objective of this research was to identify, isolate and clone a proteinase inhibitor from the haemolymph of a canegrub species with activity against the major midgut proteases of the source insect. The potential for using this canegrub-derived proteinase inhibitor as a novel source of insect resistance in transgenic sugarcane was also to be determined. The project has formed the basis of a PhD thesis submitted to the Queensland University of Technology.
Plant resistance to canegrubs : SRDC final report BSS132
(BSES, 2002) Allsopp, PG; Cox, MC; Nutt, KA
The project sought to determine the range and types of resistances to feeding by canegrubs in sugarcane clones and their wild relatives. Resistance was tested in both pot trials and field trials and the importance of several biochemical factors in this resistance was investigated.Field and pot trials showed that a range of tolerance and antibiosis resistance mechanisms to canegrub feeding exists within the current sugarcane genome and close relatives. Tolerance effects were apparent in the growth of tops, roots and stubble. Antibiosis effects were apparent on grub survival and grub growth. Some of these tolerance effects are partially correlated with the general vigour of clones, but there are a number of clones that depart from the general relationships for tolerance and antibiosis. These clones would be especially important in any future program to increase the levels of resistance within the breeding gene pool.There was reasonable repeatability of pot-based tolerance levels between pot trials and with results derived from field trials. However, the type of canegrub and its underlying biology influenced the usefulness of field trials.Biochemical investigations showed no clear relationships between any factor and antibiosis phenotypes. However, there were indications that the type of cell-wall sugars may influence resistance to canegrubs. In addition, the data clearly indicated that the quantity and type of phenolic compounds in the roots change following feeding by canegrubs.
Study tour to New Zealand, control measures for canegrubs : Final report SRD06001
(BSES, 2006) Nutt, KA; Fox, RA
Kerry Nutt and Rachael Fox visited researchers at HortResearch (Auckland and Palmerston North), Crop & Food and AgResearch (Lincoln). The CRCSIIB 1Bii project group currently uses the avidin transgene with the PPI vacuolar targeting sequence developed by scientists at HortResearch. This trip was an opportunity to discuss the progress of work with PPI-avidin, obtain methods for screening plants and ideas for identifying promising plants earlier, as well as information to help progress plants to commercialisation.