Carbon for nutrient exchange between arbuscular mycorrhizal fungi and wheat varies according to cultivar and changes in atmospheric carbon dioxide concentration

Abstract

Arbuscular mycorrhizal fungi (AMF) form symbioses with most crops, potentially improving their nutrient assimilation and growth. The effects of cultivar and atmospheric CO2 concentration ([CO2]) on wheat–AMF carbon‐for‐nutrient exchange remain critical knowledge gaps in the exploitation of AMF for future sustainable agricultural practices within the context of global climate change. We used stable and radioisotope tracers (15N, 33P, 14C) to quantify AMF‐mediated nutrient uptake and fungal acquisition of plant carbon in three wheat (Triticum aestivum L.) cultivars. We grew plants under current ambient (440 ppm) and projected future atmospheric CO2 concentrations (800 ppm). We found significant 15N transfer from fungus to plant in all cultivars, and cultivar‐specific differences in total N content. There was a trend for reduced N uptake under elevated atmospheric [CO2]. Similarly, 33P uptake via AMF was affected by cultivar and atmospheric [CO2]. Total P uptake varied significantly among wheat cultivars and was greater at the future than current atmospheric [CO2]. We found limited evidence of cultivar or atmospheric [CO2] effects on plant‐fixed carbon transfer to the mycorrhizal fungi. Our results suggest that AMF will continue to provide a route for nutrient uptake by wheat in the future, despite predicted rises in atmospheric [CO2]. Consideration should therefore be paid to cultivar‐specific AMF receptivity and function in the development of climate smart germplasm for the future.

Different wheat cultivars exhibit variable responses to inoculation with arbuscular mycorrhizal fungi from organic and conventional farms

“…Comparing the effects of organic and conventional AM fungal field inoculum on crop growth and yield can importantly inform efforts to increase the effectiveness of sustainable agriculture. It has been known that cultivars of wheat exhibit different responses to mycorrhizal fungal inoculation [11,12,19,20]. Although earlier studies found that older cultivars strongly responded to AM fungal inoculation, later studies provide mixed results [16,18,21].…”

“…Wheat cultivars associate with different AM fungal communities in their roots [17] and may respond differently to AM fungal inoculation in terms of growth, root colonization and carbon for nutrient exchange [18][19][20]. Hetrick et al [10] suggested that the age of a cultivar (i.e.…”

Cultivar‐dependent increases in mycorrhizal nutrient acquisition by barley in response to elevated CO2

“…Assimilation of N and P via AMF was quantified using 33 P and 15 N tracers when plants were 11 weeks old and were at anthesis. Based on the methods of Thirkell, Pastok, et al (2019), three cores constructed from PVC tubing (length 80 mm, diameter 18 mm), with windows (50 mm × 12 mm) cut in the lower two-thirds of each side were inserted into each of the plant pots ( Figure 1). These windows and the bottom of each core were covered in a 20 µm nylon mesh which prevented penetration by plant roots but allowed AMF hyphal ingrowth.…”

“…In both cultivars, allowing AMF access to the labeled core resulted in greater 15 N label assimilation in barley shoots, suggesting AMF contributed to N uptake. Mycorrhizal acquisition of N has been demonstrated in barley (Wilkinson et al, 2019), and wheat (Miransari et al, 2009;Thirkell, Pastok, et al, 2019;Zhu et al, 2016),…”

QTL mapping of agronomic traits in wheat using the UK Avalon × Cadenza reference mapping population grown in Kazakhstan

“…There are many examples where DH mapping populations have been used successfully for the construction of genetic maps of hexaploid wheat and QTL mapping ( Blake et al, 2019 ). One example of the prominent use of DH lines in the identification of marker-trait associations in the UK is by having a national reference population, in this case, Avalon × Cadenza (A × C) ( Griffiths et al, 2009 ; Griffiths et al, 2012 ; Allen et al, 2011 ; Bai, Liang & Hawkesford, 2013 ; Ma et al, 2015 ; Farré et al, 2016 ; Coulton et al, 2020 ; Thirkell, Pastok & Field, 2020 ), which was developed as part of the UK Wheat Genetic Improvement Network ( WGIN, 2008 ) and tested for agronomic traits in different regions the world ( Ma et al, 2015 ; Farré et al, 2016 ),…”