Pollen Dysfunction Causes ‘Floral Bud Distortion’ in Indian Soybean (Glycine max)

Floral bud distortion (FBD) is a peculiar disorder limiting yield of soybean in central India. Investigations were conducted to understand tissue-specific cytological, biochemical and molecular alterations associated with FBD. The conspicuous morphological symptom seen was extended vegetative phase, which remained green even after R7 (beginning maturity) stage of growth and failure to produce pods leading to complete yield loss in affected plants. Reduced numbers of pollen grains as well as pollens with high percent of sterility were recorded in symptomatic plants. Although the stigma was found to be receptive in the symptomatic plants, pollens showed irregular shape and had a thicker exine wall. Carbohydrate (2.21 times), protein (2.38 times) and chlorophyll (2.17 times) contents were found to be significantly higher in symptomatic plants. Tissue-specific differentially expressed TDFs (transcript-derived fragments) were generated through cDNA-RAPD using 40 primers. Seven primers were found polymorphic and size ranged from 160 to 1100 bp. Re-amplified TDFs were sequenced, and they showed partial homology with characterized (ARF, XM_003529058) and uncharacterized (LOC 100815325) transcription factors. This indicates investigating differentially expressed genes are needed to understand the insights of molecular alterations associated with floral bud distortion. © 2018, NAAS (National Academy of Agricultural Sciences).