|De Prado, Rafael|
Submitted to: International Weed Control Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/25/1996
Publication Date: N/A
Citation: N/A Interpretive Summary:
Technical Abstract: Recent research conducted with pea (Pisum sativum L.) suggests that dicotyledonous plants are graminicide resistant due to the presence of a graminicide insensitive, multi subunit (prokaryotic type) ACCase in plastids. It has also been reported that pea contains a cytosolic, multi functional (eukaryotic type) ACCase that exhibits a moderate level of graminicide tolerance. Chickpea (Cicer arietinum L.) is a major grain legume crop in the Mediterranean region. We investigated whether both types of ACCase were present in chickpea and whether they differed in graminicide tolerance. Crude extracts from chickpea leaves were desalted and applied to an FPLC anion exchange (Q Sepharose) column. Proteins were eluted with a salt (0 to 0.5 M KCl) gradient. Two peaks of ACCase activity were found. The first peak eluted at approximately 75 mM KCl and contained the 32 kDa biotinylated subunit of the multi subunit ACCase. The second peak, which eluted at approximately 200 mM KCl, contained the cytosolic, multi functional ACCase as indicated by the presence of a 220 kDa biotinylated subunit. Herbicide concentrations required to inhibit ACCase activity by 50% (I50 values) were determined for diclofop for both the multi subunit and multi functional ACCases. The multi subunit ACCase was resistant to diclofop with only 30% inhibition of activity at 100 uM. The multi functional ACCase was moderately tolerant with an I50 value of approximately 30 uM. These results are consistent with those previously reported for pea and support the conclusion that dicotyledonous plants are graminicide resistant because of the presence of a multi subunit, prokaryotic type ACCase in plastids.