Gene expression and carbohydrate content during stolon to tuber transition in potatoes (Solanum tuberosum)

Abstract

1994. Gene expression and carbohydrate content during stolon to tuber transition in potatoes (Solarium tuberosum) -Physiol. Plant. 90: 285-292.In using an efficient and synchronised in vitro tuberisation system the transition of axillary buds from stolons to tubers in Soianum tuberosum L. cv. Bintje was followed. After 5 or 6 days on tuber-inducing medium all axillarj' buds had formed tubers which increased in size until the experiment was ended at day 10. Concomitantiy with the visible appearance of tubers the fresh weight of the axillary buds increased as well as their starch content. Soluble sugar content, notably glucose, increased until tuberisatioti occurred and dropped after that. In the daily sampled explants gene expression was studied at several levels. R.HA was isolated from the different explants during the whole tuberisation experiment and northern blots were probed with cDNAs encoding genes involved in starch-and patatin-biosynthesis. It was shown that in the ver\' early stages of development hardly any transcript could be detected. Only one day before visible swelling occurred were clear signals obtained for all the genes investigated. Although it was evident that coordinate expression of starch biosynthetic genes did occur, it was not in a similar fashion for all the genes. Sucrose synthase and ADPGpyrophosphoryiase B were expressed in an identical fashion which was different from ADPG-pyrophosphorylase S. granule-bound starch synthase and branching enzyme. The RNA levels of these three latter genes reached a maximum at day 5. remaining constant until the experiment was finished. The transcript levels of sucrose synthase and ADPG-pyrophosphorj'lase B reached their highest level at day 5 after which they dropped to a lower ievel at day 10. Patatin gene expression was clearly different from that of the starch biosynthetic genes: it steadily increased from day 4 until the end of the experiment. Enzyme activities of sucrose synthase. ADPG-pyrophosphorylase and branching enzyme confirmed the RNA expression data and showed that ADPGpyrophosphorylase enzyme activity reached a maximum at day 4 after which it dropped. The other two enzyme activities could be detected at or one day after tuberisation occurred and increased until the experiment was ended.

Visualization of differential gene expression using a novel method of RNA fingerprinting based on AFLP: Analysis of gene expression during potato tuber development

“…The expression profile in the cDNA-AFLP data gives a picture very comparable to the Northern data presented here and in other papers (Park et al, 1985;Visser et aL, 1994). Very high abundance of a particular transcript such as is the case with patatin can result in the occurrence of characteristic artefacts.…”

“…Previous studies have shown the induction of patatin and AGPase in an in vitro tuberization system (Hendriks et aL, 1991;Visser et aL, 1994). We show here that the cDNA-AFLP method faithfully reproduces these results.…”

“…Several investigations have shown that these conditions produce tubers that closely mimic those of in vivo grown tubers on physiological, biochemical and genetic levels (Hannapel, 1991;Paiva etal., 1982;Visser et aL, 1994). The advantages of a synchronized tuberization system for the dissection of molecular processes involved in tuber formation has been long recognized (Bourque et al, 1987) and this is especially the case for gene expression studies.…”

“…Bintje) were as described (Visser et aL, 1994). Material for template production was harvested daily and immediately frozen in liquid N 2.…”

Starch synthesis‐, and tuber storage protein genes are differently expressed in Solanum tuberosum and in Solanum brevidens

“…and in S. brevidens Although the expression of the genes involved in starch synthesis is characteristic for potato tuber development [23], no corresponding cDNAs have been isolated from S. tuberosum by differential screening using S. brevidens as a negative partner. Therefore, we have decided to check the expression of these genes in developing shoots and tubers by Northern hybridization experiment.…”