Molecular Soil Biology 2025, Vol.16, No.3, 150-161 http://bioscipublisher.com/index.php/msb 154 on wheat roots. Different soil and pH values will change the number and growth of AMF species, and will also affect the effect of wheat nutrient absorption and growth. If the soil is too acidic, too alkaline, too dry or too wet, it will make it more difficult for AMF to colonize and its function will be weakened. However, AMF itself has some adaptability, and they can cope with these harsh environments to a certain extent (Lenoir et al., 2016; Tedersoo and Bahram, 2019; Dhiman et al., 2022). The effect of water on mycorrhiza is particularly obvious. Appropriate humidity is conducive to the formation of mycorrhiza and helps it cooperate better with wheat (Lenoir et al., 2016; Dhiman et al., 2022). 5.2 Impact of fertilizer regimes and tillage practices The amount and type of fertilization will affect the number and function of AMF. Generally speaking, too much nitrogen and phosphorus fertilizer will reduce the number of AMF and reduce the colonization ability. Studies have found that the number of mycorrhizae will decrease by about 32% after applying phosphorus fertilizer, and nitrogen fertilizer will decrease by 15% (Treseder, 2004). This is because when there are enough nutrients in the soil, plants are less "dependent" on AMF. This phenomenon is also called the "plant investment hypothesis." In addition to fertilization, the way of tillage also has an impact. If protective tillage methods are used, such as not deep plowing the land and planting perennial crops, it will be more conducive to the survival of beneficial bacteria and help AMF to better colonize and play a role (Jacott et al., 2017; McKenna et al., 2025). If crop varieties that are more responsive to AMF are selected in breeding, it may also help to increase crop yields and improve soil health (McKenna et al., 2025). 5.3 Environmental stresses (salinity, drought) and mycorrhizal buffering effects When wheat encounters adverse environments such as salinity or drought, AMF can play a great role. They regulate key substances such as aquaporins and polyamines, allowing plants to absorb more water and nutrients and reduce damage (Nadeem et al., 2014; Lenoir et al., 2016; Sharma et al., 2021; Branco et al., 2022; Dhiman et al., 2022). Under these adversities, AMF can also help wheat reduce water loss, control the entry of harmful ions, and enhance the antioxidant system by regulating gene expression (Nadeem et al., 2014; Sharma et al., 2021). AMF can also work with some beneficial rhizosphere bacteria (also called PGPR), and this combination can further improve wheat's growth ability and yield in difficult environments (Nadeem et al., 2014). 6 Genetic Variability in Wheat-Mycorrhizal Symbiosis 6.1 Differences among wheat genotypes in responsiveness to AMF Many studies have found that different wheat genotypes have significant differences when they coexist with arbuscular mycorrhizal fungi (AMF). Some varieties are more susceptible to AMF colonization and have better results. Lehnert et al. (2017) tested 94 bread wheat varieties and found that their ability to be colonized by AMF in the roots varied greatly, and this difference can be mapped to some genetic regions (QTLs). Among 127 durum wheat materials, different varieties responded differently to different AMF types, and the study divided them into 6 genetic groups (Ganugi et al., 2021). Some field experiments have also found that even with large environmental changes, the AMF colonization rates between 10 modern winter wheat varieties still show fixed differences, indicating that the genetic background of the variety itself is also important (Veršulienė et al., 2024) (Figure 3). Thirkell et al. (2022) conducted another study using a double haploid population of spring wheat and found that some genotypes grew better after symbiosis with AMF, while others grew worse, indicating that wheat's response to AMF varies greatly. 6.2 Molecular and genetic basis of AMF colonization in wheat Scientists have found a lot of genetic information related to wheat and AMF symbiosis. Using the genome-wide association analysis (GWAS) method, people have found multiple gene regions (QTLs) related to AMF colonization. In bread wheat, the study found 6 QTLs, mainly distributed on chromosomes 3A, 4A and 7A (Lehnert et al., 2017); in durum wheat, there are 7 QTLs located on chromosomes 1A, 2B, 5A, 6A, 7A and 7B (De Vita et al., 2018). These gene regions may affect the mutual recognition between plants and fungi, protein degradation, nutrient balance and disease resistance. Some gene families are also closely related to AMF colonization, such as the LAC (laccase) and NL (nodulin-like) families. Studies have found that some LAC genes
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