Temperature controls both gametophytic and sporophytic development in microspore cultures of Brassica napus

Abstract

Temperature controls the developmental fate of isolated Brassica napus microspores in vitro. Culture at 32.5°C leads to sporophytic development and the formation of embryos. Here we show that culture at 17.5°C leads to gametophytic development, and the formation of pollen-like structures at high frequencies (up to 80% after 7 days in culture). Early stages of both developmental pathways are observed in culture at 25.0°C, and embryos are produced at low frequencies (0.7%) at that temperature. Culturing B. napus microspores at 32.5°C versus 17.5°C brings the switch from gametophytic to sporophytic development under simple experimental control and provides a convenient tool for investigating the cellular and molecular mechanisms controlling this developmental switch.

Microspore embryogenesis in barley: anther pre-treatment stimulates plant defence gene expression

“…Several abiotic stresses, alone or in combination, are used to trigger ME. These include cold shock (Gonzalez and Jouve 2005;Labbani et al 2005), heat-shock (Custers et al 1994;Touraev et al 1996;Rimberia et al 2005), osmotic shock (Caredda et al 2000;Touraev et al 2001;Li and Devaux 2003;Wojnarowiez et al 2004), pH variation (Barinova et al 2004), nutrient starvation (Touraev et al 1996), exposure to heavy metals, such as lithium (Zonia and Tupy 1995) or copper sulphate (Wojnarowiez et al 2002). In barley anthers, ME is induced using a combined coldand osmotic shock treatment (Caredda et al 2000).…”

Microspore derived embryo formation and doubled haploid plant production in broccoli (Brassica oleracea L. var italica) according to nutritional and environmental conditions

“…In B. napus, the most efficient induction is obtained by increasing the culture temperature to 32°C for a minimum of 8 h (Custers et al, 1994;Pechan et al, 1991). Binarova et al (1997) reported that DNA synthesis was initiated in both generative and vegetative nuclei by the application of heat stress treatment.…”

Microspore Embryogenesis

“…Also in some plant species, stress-induced pollen embryogenesis occurs at the bi-nucleate stage, at which time the pollen cell has already undergone an initial asymmetric division, resulting in two very unequal-sized cells. This does not preclude embryogenic development in bi-nucleate B. napus microspores when subjected to heat shock at 32 0 C (Custers et al 1994) and in late bi-nucleate pollen by an extra heat shock treatment at 41 0 C (Binarova et al, 1997).…”