Chromosome endoreduplication as a factor of salt adaptation in Sorghum bicolor

Abstract

Nuclear DNA amounts were measured by Feulgen cytophotometry in Sorghum bicolor cv. 610 plants early exposed to 150 mM NaCl, a treatment known to induce an increased tolerance to salinity in plants carrying this genotype. In salt-treated plants, the percentages of 8C, 16C, and 32C nuclei in roots in the primary state of growth were 21.9%, 13.3%, and 4.3%, respectively. By contrast, in nonsalinized plants, only 3.5% of the nuclei had an 8C content and no higher DNA contents were observed. The salt treatment induced chromosome endoreduplication during the differentiation of cells in the root cortex, where 41.2% of the cells displayed a DNA content higher than 4C (versus 1.3% in control plants). No enhancement of endopolyploidy was observed in cells of the root vascular cylinder or the leaves of the salt-treated plants. In another S. bicolor genotype (DK 34-Alabama), noncompetent for salt adaptation, the same NaCl treatment did not induce chromosome endoreduplication in root cortex cells. Endopolyploidy may be considered as a part of the adaptive response of S. bicolor competent genotypes to salinity.

Evidence for karyoplasmic homeostasis during endoreduplication and a ploidy-dependent increase in gene transcription during tomato fruit growth

“…As an inducer of nuclear DNA amplification, endoreduplication has been proposed to provide a means to sustain growth under adverse environmental conditions, such as genotoxic stress (Hase et al, 2006;Adachi et al, 2011), saline stress (Ceccarelli et al, 2006), water deficit (Cookson et al, 2006) and low temperature (Barow, 2006).…”

The “Polyploid Hop”: Shifting Challenges and Opportunities Over the Evolutionary Lifespan of Genome Duplications

“…For example, in Medicago and sorghum root endopolyploidy correlates with salt tolerance (Ceccarelli et al, 2006;Elmaghrabi et al, 2013) and can be induced by salt in tolerant, but not sensitive, strains (Ceccarelli et al, 2006). Thus, the ability to induce endopolyploidy may be responsible for salinity tolerance, perhaps due to cell size changes in the roots that alter ion uptake.…”

Gene Duplication to Reveal Adaptation Clue of Plant to Environmental Stress: A Case Study of NBS-LRR Genes in Soybean

“…A consistent polyploidy of yeast strains was observed to play an important role in adaptation. Similarly in plant, polyploidy has been linked to resistance to high salt concentrations in citrus (Saleh et al, 2008) and sorghum (Ceccarelli et al, 2006), suggesting that polyploidy is likely a general physiological adaptive response to osmotic stress (Dhar et al, 2011). Duplication-induced metal resistance in different plant species might be related to export of the cations outside cell (Kondrashov and Kondrashov, 2006).…”