Dear Atul,

Glomalin is a AMF originated protein help in the aggregate formation of the soil. There is good paper which describe the interlink of the glomalin and the AMF by S.F. Wright and A. Upadhyaya.

Kindly go through the article as below.

S.F. Wright and A. Upadhyaya.A survey of soils for aggregate stability and glomalin, a glycoprotein produced by hyphae of arbuscular mycorrhizal fungi. Plant and Soil 198: 97–107, 1998.

Kindly go through this link for your query;

http://dx.doi.org/10.1080/15324982.2014.944246

It should be but we need to have substantial data to support it. It is being generated.

In a 4-year study at the Henry A. Wallace Beltsville (Maryland) Agricultural Research Center, Sara F Wright found that glomalin levels rose each year after no-till was started. No-till refers to a modern conservation practice that uses equipment to plant seeds with no prior plowing. This practice was developed to protect soil from erosion by keeping fields covered with crop residue.

Glomalin went from 1.3 milligrams per gram of soil (mg/g) after the first year to 1.7 mg/g after the third. A nearby field that was plowed and planted each year had only 0.7 mg/g. In comparison, the soil under a 15-year-old buffer strip of grass had 2.7 mg/g.

We need to know at said concentration of Glomalin what is the community structure and population of AM.

I guess it is difficult the link glomelin exactly with AM fungi because glomelin estimatin should be perfect, of course there are several bacteria generated gums in the soil or rhizosphere.

You can refer this article for more information 

Glomalin: an arbuscular mycorrhizal fungal soil protein

I infer that you are asking if glomalin is a suitable proxy for estimation of arbuscular mycorrhizal fungus (AMF) extraradical hypha length or biomass in soil.  The most pertinent reference of which I am aware is:

Lovelock, CE; Wright, SF; Nichols, KA.  2004.  Using glomalin as an indicator for arbuscular mycorrhizal hyphal growth: an example from a tropical rain forest soil.  SOIL BIOLOGY & BIOCHEMISTRY 36(6):1009-1012.

If you are asking about quantification of AMF in roots, then see:

Rosier, CL; Piotrowski, JS; Hoye, AT; Rillig, MC.  2008.  Intraradical protein and glomalin as a tool for quantifying arbuscular mycorrhizal root colonization.  PEDOBIOLOGIA  52:41-50.

In either case, both papers suggest that different AMF species may produce different amounts of glomalin per unit of hyphae, so that will severely constrain the use of glomalin as a proxy for total hypha abundance of a community that is an unknown mixture of AMF species.  Moreover, the two most common ways of quantifying the amount of glomalin-related soil protein (GRSP) in a soil extract, the Bradford protein assay and ELISA with MAb 32B11, respectively likely overestimate and underestimate GRSP.  For some problems with methods of glomalin extraction and measurement see:

Janos, DP; Garamszegi, S; Beltran, B.  2008.  Glomalin extraction and measurement.  SOIL BIOLOGY & BIOCHEMISTRY  40:728-739.

If you are seeking a biochemical technique for quantifying AMF in soil, then neutral lipid fatty acids might be a good candidate.  See:

Vestberg, M; Palojarvi, A; Pitkanen, T; et al.  2012.  Neutral lipid fatty acid analysis is a sensitive marker for quantitative estimation of arbuscular mycorrhizal fungi in agricultural soil with crops of different mycotrophy.  AGRICULTURAL AND FOOD SCIENCE 21(1):12-27.

Nevertheless, at the present state of development, any biochemical technique would have to be calibrated against morphology-based assessments of hypha abundance, so it probably is simplest and most direct to just extract and microscopically measure extraradical hyphae.