Potato Protoplasts in Crop Improvement

Abstract

Clonal populations regenerated from single-leaf cell protoplasts of the potato cultivar ;Russet Burbank' display a high frequency of variation for several horticultural and disease resistance characters. Observations over a period of three tuber generations suggest stable changes in tuber shape, yield, and maturity date, in photo-period requirements for flowering, and in plant morphology. Enhanced resistance to early blight (Alternaria solani) and late blight (Phytophthora infestans) diseases also regularly occurs within regenerated populations. These findings are discussed in the context of possible application to varietal improvement, particularly as they pertain to asexually propagated plants.

Proteins Produced during Salt Stress in Tobacco Cell Culture

“…There have been several reports of the selection of cell lines which show increased resistance to disease, to herbicides, and to various stresses such as low water potential (PEGinduced), cold, or salt (3,4,23,26). Very little is known about the biochemical and genetic basis for the resistance exhibited by these selected cell lines, although it is evident that adaptation to PEG or salt entails some osmotic adjustment.…”

Plant Regeneration, Somaclonal Variation and Resistance to Late-blight in Tomato

“…These mutations affect developmental function such as leaf shape, seedlings height and lethal seedling (albino) in this study. There is frequent recovery of mutant in the R 1 generation (Shepard et al, 1980;Gavazzi et al, 1987). Evidence is lacking on their origin, however whatever the basis of this phenomenon, this is not new in the literature (Evans and Sharp, 1983;Larkin and Scowcroft, 1983).…”

“…For instance, 72 percent variants have been reported in rice regenerants (Sun et al, 1983). There is evidence that increased resistance to fungal pathogens can be generated by somaclonal variation (Shepard et al, 1980). The most difficult obstacle in identifying the optimum In vitro treatment is that the occurrence of lines with improved traits is a rare event, the majority of variants produced being inferior in some respect to the parent.…”

L'épigénique

“…En outre, entre l'événement de fusion et le moment où une morphogenèse s'organise, il peut s'écouler un délai très long (6 mois à l an). Durant toute cette période, des mutations, des remaniements chromosomiques, ou des déviations épigéniques peuvent être source de variations (Maliga et coll., 1978 ;Shepard, 1980). Des résultats expérimentaux dans plusieurs laboratoires font 1 'inventaire des divers types de variants après passage par le stade protoplaste même en 1 'absence de fusion ; en particulier à Orsay sur Pétunia (données non publiées) ont été mises en évidence des hérédités épigéniques.…”