David W. Altman

The stereochemistry of the biosynthetic precursor of gossypol

cis-trans-Farnesyl pyrophosphate or an equivalent such as nerolidyl pyrophosphate in contrast to earlier work, has been established, through [1,2-13C2]acetate feeding, as the main biosynthetic precursor of gossypol in chilled cotton (Gossypium arboreum) radicals.

Interaction of cotton tissue culture cells andVerticillium dahliae

SummaryElicitation of sesquiterpenoid aldehyde phytoalexins inGossypium arboreum cell suspension cultures was confirmed by thin layer chromatography, high performance reverse phase liquid chromatography, and an aniline-reaction assay after inoculation with heat-treated conidia ofVerticillium dahliae A 2.3X mean increase in total terpenoids was observed. Component phytoalexins varied, with either hemigossypol and gossypol being detected or the O-methylated terpenoids hemigossypol-6-methyl ether and related compounds. Long-termGossypium suspension cultures were mixoploid with an increase in chromosome number and mean DNA content. Addition ofV. dahliae elicitor(s) to the medium for embryo-proliferating callus ofG. hirsutum inhibited growth and embryo production with a linear correlation (r=−0.87;P<0.01) between the elicitor concentration and the number of embryos. Addition of14C-labeled NaOAc to suspension cells gave 30% incorporation, and from13C-NaOAc addition, labeled sesquiterpenoid aldehydes were recovered. The cotton-Verticillium system is another case of secondary metabolite elicitation in plant tissue culture and might be used for basic studies of hostpathogen interaction as well as for a selection tool to obtain resistance to an important disease.

RAIMONDALONE, A SESQUITERPENE FROM A COTTON INTERSPECIFIC HYBRID

Abstract A new sesquiterpenoid, raimondalone (8-formyl-6,7-dihydroxy-5-isopropyl-2-methoxy-3-methyl-1,4-naphthoquinone), has been isolated from the leaves of a cotton plant derived from an interspecific hybrid ( G. hirsutum x G. raimondii ). The structure of this compound and the 13 C chemical shifts of related compounds were determined using 2D HMBC NMR spectrometry.

Quantitative trait variation in phenotypically normal regenerants of cotton

SummarySomaclonal variation for quantitative traits could affect the practical utilization of regenerants in cotton improvement. Three groups of experimental lines were derived to analyze variation, including one control group from the explant-source cultivar and two groups of R3 somaclones from different R0’s (R0 = initial regenerant) free of observable chromosomal rearrangements. A three-environment field trial was conducted to evaluate group means, genetic variance, and line performance. Mean seedcotton yields of the somaclonal groups were reduced by 21 and 26% relative to the Coker 310 standard at two locations, but lint percentage and certain fiber properties were improved. Group-by-environment interactions were significant (P<0.05) for 10 of the 12 measured traits. Genetic variance tended to decrease in the somaclones, plant height being an exception. Line performance of the somaclones indicated that 50-boll weight, seed index, and fiber length did not reach the Coker 310 group means. These data suggest that genetic gain will be improved if regenerants of cotton are self-pollinated and the progenies evaluated for quantitative traits before crossing somaclones with the explantsource cultivar or other elite germplasm.

Message from the president and the secretary of the IAPTC&B

We are pleased to present in this issue of the journal two feature articles. Dr John C. Sanford, in his Turning Points article, provides a most interesting and fascinating account of the conception and early history of the biolistics process for the direct delivery of DNA into plant cells. In a few short years it has become one of the most widely used and important methods for the genetic transformation of plants, in addition to its increasing use in medicine. This valuable historical record once again demonstrates the value and rewards of pursuing bold, unconventional and novel ideas. There is much international debate these days about the introduction of transgenic crops/foods. The My Turn article by Dr Willy de Greef (Switzerland) presents another important facet of this debate, namely the moral imperatives in the application of agricultural biotechnology to the problems of food security in the developing and poorer nations of the world. The IAPTC&B has traditionally published a membership directory once every 4 years. The current officers have striven to maintain low membership dues for international activities while improving the quality of services, as exemplified by the publication of two special annual issues of the journal In Vitro ± Plant as the official IAPTC&B journal. In order to provide our members convenient and instant access to the membership directory, and without the expense of a printed and often outdated directory, the entire membership list has been posted on the IAPTC&B website. We are currently looking into the possibility of providing our members with access to AgBiotechNet, an Internet service for agricultural biotechnology produced by CABI Publishing (the publishers of In Vitro-Plant). CABI has organized free 60 day trials for IAPTC&B members. Simply register for free access at http://www.agbiotechnet.com/iaptcb/ during September and October 2000 and you will receive a username and password for 60 days of access. Please let us know what you think of the service so that we can come to the best arrangements concerning preferential rates for IAPTC&B members. The First Circular of the 10th IAPTC&B Congress is included in this copy of the journal, along with the preliminary list of program topics for plenary lectures and symposia. We encourage all of our members, as well as other interested individuals, to return the Information Request Form to the IAPTC&B Congress Secretariat, indicating their preferences. We are deeply saddened to inform the IAPTC&B family of the very untimely death of our friend and colleague, Dr Abed Watad, who served as the Secretary±Treasurer of the IAPTC&B during 1994±98 (see Obituary by Professor Arie Altman). Abed passed away on March 15, 2000, after a long and valiant battle with cancer. One of us (I.K.V.) knew Abed and his charming family well, and had the pleasure of working with him closely for many years on a research project of mutual interest in Israel. In his short life of 43 years, Abed made important and lasting contributions not only as a scientist, but also as an exceptionally thoughtful and kind human being, and a loving husband and father. We offer our deepest condolences, and love, to his wife Yussra, the children (Marwah, Hassan, and Mohammad), and the Watad family.