Root sampling and RNA extraction methods for field-based gene expression analysis of soybeans

Isolation of an adequate quantity of high-quality RNA is a crucial step in gene expression analysis. Difficulties in sampling and RNA extraction of field-grown crops, especially from roots, are substantial obstacles to understanding actual gene expression in the field. We examined the effectiveness of the RNA extraction method (FRP) using pot- and field-grown soybean roots. High quantity and quality of total RNA could extract by the FRP method from both pot- and field-grown soybean roots at different growth stages. To determine the influence of root washing during the sampling process, roots were washed with water for 5 s, 1 min, and 5 min, then analyzed for aquaporin gene expression levels. Root washing for 5 min affected gene expression of some aquaporins. To obtain RNA that reflects the correct gene expression profile, it is necessary to minimize the effects of the sampling process.