PSI-K is a subunit of photosystem I. The function of PSI-K was characterized in

Resistance to Ascochyta blight has been demonstrated within pea germplasm. Pea genotypes show dif-Ascochyta blight of pea (Pisum sativum L.) is a fungal disease ferences in resistance or susceptibility to M. pinodes and caused by Mycosphaerella pinodes (Berk. & Bloxham) Verstergren, P. medicaginis var. pinodella that is independent of the Phoma medicaginis Malbr. & Roum. var. pinodella (L.K. Jones) Boerema, and Ascochyta pisi Lib. that can result in significant reduc-virulence of the pathogen isolate (Onfroy et al., 1999; tions to pea yield and quality. To characterize the genetics of resistance Wroth, 1998a; Xue et al., 1998). Complete resistance to and to identify molecular markers for use in plant breeding, quantitainfection by either pathogen has not been observed in tive trait loci (QTLs) affecting Ascochyta blight resistance were pea. Using different germplasm, Wroth (1999) found mapped in F 2:3 and F 2:4 families produced from a cross between resistant that resistance to M. pinodes infection showed quantibreeding line 3148-A88 and susceptible cultivar Rovar. A linkage map tative inheritance, while Clulow et al. (1991) suggested containing 96 loci on 11 linkage groups was constructed for 133 families that resistance to M. pinodes showed major gene inherfrom this cross. Resistance of progeny lines to natural Ascochyta itance. blight epidemics was examined in field trials at Medina, Western Molecular linkage maps and mapping of QTLs are Australia, in 1997, 1998, and 1999. Disease severity was assessed on valuable tools for characterizing the genetics of disease stems, leaves, and pods by means of separate rating scales. Because pea shows increased susceptibility to Ascochyta blight as it matures, resistance, localizing resistance loci on linkage maps, plant reproductive stage was assessed at the time of disease scoring and identifying linked polymorphic DNA sequences in the 1998 and 1999 trials. Thirteen QTLs were detected for Ascothat might be used for marker-assisted selection (MAS) chyta blight resistance on seven linkage groups. Eight of these QTLs during plant breeding. QTL mapping has characterized were detected in multiple environments or by multiple trait scores.

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A novel starch bread that contained no gluten was found to firm at a rate comparable to a normal standard bread made from wheat flour. Treatment of both the starch and the standard bread with Novamyl, an antistaling enzyme mix, inhibited firming. 13C CP/MAS NMR studies showed that the decreased firming of the Novamyl‐treated starch bread was correlated with decreased starch retrogradation. For the Novamyl‐treated bread the increase in retrograded starch over six days following baking was about 11% compared to an increase of over 200% for the untreated bread. These results suggests that starch retrogradation is sufficient to cause bread firming.

Arabidopsis thaliana plants lacking the PSI-H or PSI-L subunit of photosystem I have been shown to be severely affected in their ability to perform state transitions, but no visual phenotype was observed when these plants were grown under different light quantities and qualities. However, the chloroplasts in the PSI-H- and PSI-L-less plants contained fewer and more extended grana stacks. The plants lacking PSI-H or PSI-L were characterised with respect to their photosynthetic performance. Wild-type plants adjusted the non-photochemical fluorescence quenching to maintain constant levels of PSII quantum yield and reduction of the plastoquinone pool. In contrast, the plants deficient in state transitions had a more reduced plastoquinone pool and consequently, a less efficient PSII-photochemistry under growth-light conditions and in state 2. The maximal photosynthetic capacity and the quantum efficiency of oxygen evolution were diminished by 8-14% in the PSI-H-less plants. Under growth-light conditions, the stroma was similarly reduced in the PSI-H-less plants and the rate of cyclic electron transport was unchanged. Pigment analysis showed that the xanthophyll cycle was not upregulated in order to compensate for the lack of state transitions. In general, the plants lacking PSI-H and PSI-L showed a decreased ability to optimise photosynthesis according to the light conditions.