Agrobacterium-mediated transformation of cotton (Gossypium hirsutum L.) with a fungal phytase gene improves phosphorus acquisition

Abstract

A phytase gene (phyA), isolated from Aspergillus ficuum (AF537344), was introduced into cotton (Gossypium hirsutum L.) by Agrobacteriummediated transformation to increase the phosphorus (P) acquisition efficiency of cotton. Southern and Northern blot analyses showed that the phyA was successfully incorporated into the cotton genome and expressed in transgenic lines. After growing for 45 days with phytate (Po) as the only P source, the shoot and root dry weights of the transgenic plants all increased by nearly 2.0-fold relative to those of wildtype plants, but were similar to those of transgenic plants supplied with inorganic phosphorus. The phytase activities of root extracts prepared from transgenic plants were 2.4-to 3.6-fold higher than those from wild-type plants, and the extracellular phytase activities of transgenic plants were also 4.2-to 6.3-fold higher. Furthermore, the expressed phytase was secreted into the rhizospheres as demonstrated by enzyme activity staining. The transgenic plants accumulated much higher contents of total P (up to 2.1-fold after 30 days of growth) than the wildtype plants when supplied with Po. These findings clearly showed that cotton plant transformed with a fungal phytase gene was able to secret the enzyme from the root, which markedly improved the plant's ability to utilize P from phytate. This may serve as a promising step toward the development of new cotton cultivars with improved phosphorus acquisition.

Molecular mechanisms underlying phosphate sensing, signaling, and adaptation in plants

“…Among them, overexpression of phytase and phosphatase genes has generally resulted in an increase in P efficiency of host plants, regardless of the origin of the genes. Notable examples include AtPAP15 in soybean (Wang et al ), MtPHY1 in clover (Ma et al ), OsPAP10a in rice (Tian et al ), PhyA from Aspergillus niger in clover, cotton, and rapeseed (George et al ; Liu et al ; Wang et al ), and appA from Escherichia coli in potato and rapeseed (Hong et al ; Wang et al ).…”

Improved phosphate metabolism and biomass production by overexpression of AtPAP18 in tobacco

“…For instance, the overexpressions of two plant PAP-encoding genes, AtPAP15 ) and MtPAP1 (Xiao et al 2006), with phytase activity and a fungal phytase gene, phyA (Richardson et al 2001;Liu et al 2011), have been shown to have increased P acquisition and improved crop yield on soils with low Pi. Here, we have reported the overexpression AtPAP18 in Nicotiana tabbacum as a crop model plant that led to remarkable increases in APase activity, total P and free Pi contents and biomass production.…”

A discussion on cotton transformation during the last decade (2010–2021); an update on present trends and future prospects

“…Long cotton fibers obtained from stressed conditions were spun into yarn that was observed to be uniform and have more strength (Mittal et al 2015). For instance, improved phosphorus acquisition in cotton was obtained by Liu et al (2011a) via Agrobacterium-mediated transformation and particle bombardment (Liu et al 2011b) with phytase gene (phy A) obtained from Aspergillus ficuum. Generally, amount of potassium found in soil is not sufficient to meet the needs of plant growth.…”