Location: Agroecosystem Management Research
Title: Arbuscular mycorrhizal fungi differ in their ability to regulate the expression of phosphate transportors in maize (Zea mays L.) Authors
Submitted to: Mycorrhiza
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 18, 2013
Publication Date: March 7, 2013
Repository URL: http://handle.nal.usda.gov/10113/57994
Citation: Tian, H., Drijber, R.A., Li, X., Miller, D.N., Wienhold, B.J. 2013. Arbuscular mycorrhizal fungi differ in their ability to regulate the expression of phosphate transportors in maize (Zea mays L.). Mycorrhiza. Available: http://link.springer.com/article/10.1007/s00572-013-0491-1/fulltext.html. Interpretive Summary: Molecular methods were used to identify mycorrhizal species infecting maize grown in rotation with soybean. Long-term N fertilization did not reduce the incidence of mycorrhizal infection. A greenhouse experiment was conducted to study the expression of an epidermal-expressed phosphorus transporter gene and an arbuscular mycorrhizal specific induced phosphorus transporter gene in maize either colonized or not colonized by mycorrhiza. Expression of the mycorrhizal specific P transporter gene activity was positively correlated with mycorrhizal biomass on maize roots, plant P uptake and shoot weight but negatively correlated with epidermal-expressed P transporter gene activity.
Technical Abstract: A greenhouse experiment was conducted to study the expression of two phosphate (P) transporter genes ZEAma:Pht1;3 (epidermal-expressed) and ZEAma:Pht1;6 (AM specific induced, and expressed around arbuscules) in maize root to colonization by different arbuscular mycorrhizal (AM) fungal inoculants. Non-mycorrhizal maize, maize colonized by Glomus deserticola (CA113), Glomus intraradices (IA506), Glomus mosseae (CA201), Gigaspora gigantean (MN922A) and the co-inoculation of all four species were established. Plant materials were harvest after nine weeks, and root length colonized by AM fungi, AM fatty acid biomarkers, biomass of shoots and P uptake in shoot were measured. The expression patterns of the two genes were quantified using Real-time RT-PCR. Different AM inoculations showed distinct functional diversity in P uptake or growth. The expression level of ZEAma:Pht1;6 was 26-135 times higher in AM plants than in non-mycorrhizal maize roots; whereas the expression level of ZEAma:Pht1;3 was 5-44 times lower in AM plants than in non-mycorrhizal plants. Expression of the two genes differed with inoculation treatment and increasing the diversity of AM fungi in maize roots led to greater expression of ZEAma:Pht1;6 as well as P uptake in shoots. The expression of ZEAma:Pht1;6 was significantly positively correlated with AM biomass in maize roots, P uptake and dry weight of shoot, but negatively correlated with the expression of ZEAma:Pht1;3. Addition of P fertilizer at low concentration significantly increased the expression of ZEAma:Pht1;6, but had no effect on the expression of ZEAma:Pht1;3.