Self-incompatibility

It is likely sigifificant that L. glaberrima is self-compatible, whereas most other species of Lasthenia are self-incompatible. Long-distance dispersal of a single propagule of L. glaberrima would then have been sufficient to establish the species in Chile. It is, of course, entirely possible that propagules from one or another of the self-incompatible species could also have made the journey, but without a reproduc-tively compatible partner their fates were sealed. 

At a cellular and genetic level there are many similarities between self incompatibility and the incompatible defense response. The fact that proteins can work together to determine the outcome of an interaction suggest that PGIP could... 

Unilateral incompatibility is a phenomenon in which self-compatible species can be crossed as a female, but not as a male, to self-incompatible species (Abdalla and Hermsen, 1972). Pollen tubes fail to penetrate stylar tissue in self-incompatible (female) X self-compatible (male) crosses. Although most diploid Solarium species are self-incompatible, the Mexican species S. verrucosum is self-compatible. Dinu et al. (2005) found that S. verrucosum could be crossed as a female, but not as a male, to self-incompatible species. It is sometimes possible to find exceptional plants that do not exhibit unilateral incompatibility in self-incompatible X selfcompatible interspecific crosses (Pandey, 1962). The identification of such plants allows a breeder to overcome the unilateral incompatibility crossing barrier. For example, exceptional plants ( acceptors ) that accept S. verrucosum pollen and produce fertile hybrids have been reported (Eijlander et al., 2000). It is interesting that some acceptor plants will accept pollen... 

Hosaka, K., Hanneman, R. E. Jr. (1998a). Genetics of self-compatibility in a self-incompatible wild diploid potato species Solanum chacoense. 1. Detection of an S locus inhibitor (Sli) gene. Euphytica, 99, 191-197. 

Tanksley, S. D., Loaiza-Figueroa, F. (1985). Gametophytic self-incompatibility is controlled by a single major locus on chromosome 1 in Lycopersicon peruvianum. Proceedings of the National Academy of Sciences, USA 82, 5093-5096. 

In classical genetic self-incompatability systems, the site of pollen tube inhibition is on the stigma surface or somewhere in the style. A pollen grain may fail to genninate, or produces a tube that grows abnonnally and is soon occluded by callose, or... 

Mulcahy, D.L., and G.B. Mulcahy. 1983. Gametophyte self-incompatability re- examined. Science 220 1247-1251. 

Variations of the life cycle occur. For example, a process called apomixis leads to asexual formation of seed.469 In many plants, including maize, separate flowers form the ovule and the pollen. This is one mechanism for avoiding inbreeding.470 In many plants systems of self-incompatibility have evolved.471 In some, e.g., Arabidopsis and other crucifers, pollen germination is disrupted unless it falls on a stigma possessing a different allele-specific receptor. In other cases development of the pollen tube is disrupted at a later stage. In maize and in more than 150 other... 

S locus cysteine-rich protein self-incompatibility S locus glycoprotein S locus receptor-like kinase systemic wound response protein... 

Pollination of Helianthus species is predominantly by honeybees and bumblebees (Cockerell, 1914), although other insects may be active. Helianthus are all-day flowers, presenting a continuous pollen and nectar resource for bees and other insects. Jerusalem artichoke, like nearly all Helianthus species, is largely self-incompatible, and as a consequence, cross-pollination is essential for the production of viable seed, with self-pollination being a rare event. 

CUI, Y. H BRUGIERE, N JACKMAN, L SI, Y. M., ROTHSTEIN, S. J., Structural and transcriptional comparative analysis of the S locus regions in two self-incompatible Brassica napus lines., Plant Cell., 1999,11, 2217-2231. 

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