FULL-LENGTH RESEARCH ARTICLE Pollen Dysfunction Causes ‘Floral Bud Distortion’ in Indian Soybean (Glycine max) Rachana S. Wakekar 1 • Pravin V. Jadhav 1 • Prashant B. Kale 1 • Mangesh P. Moharil 1 • Ravindra S. Nandanwar 1 • Shyamsundar S. Mane 2 • Amit G. Deshmukh 3 • Joy Manjaya 4 • Raviprakash G. Dani 1 Received: 18 January 2015 / Accepted: 8 January 2018 Ó NAAS (National Academy of Agricultural Sciences) 2018 Abstract 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. Keywords Soybean  Floral bud distortion  Pollen anatomy  Pollen viability Abbreviations ARF: Auxin response factor; AuxREs: Auxin response elements; BLAST: Basic local alignment search tool; BPMV: Bean pod mottle virus; cDNA: Complementary Deoxyribonucleic Acid; CHS: Chalcone synthase; FBD: Floral bud distortion; FTIR: Fourier-transform infrared spectroscopy; HPLC: High-performance liquid chromatography; IDVs: Intensity-derived values; NCBI: National center for biotechnology information; PTGS: Posttranscriptional gene silencing; RAPD: Randomly amplified polymorphic DNA; RNA: Ribonucleic acid; SEM: Scanning electron microscopy; SMV: Soybean mosaic virus; TDFs: Transcript-derived fragments; TSC: Total soluble carbohydrate; TSV: Tobacco streak virus Introduction Siphonogamy is a key event in the reproductive course of plants and has been extensively studied in the past. How- ever, in recent years, the occurrence of ‘floral bud distor- tion’ (FBD) in soybean has been observed in the main soybean-growing regions of central India. This is a con- dition where the plant fails to produce pods and does not reach the maturity stage, but continues to remain green & Pravin V. Jadhav jpraveen26@yahoo.co.in 1 Biotechnology Centre, Department of Agricultural Biotechnology, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, Maharashtra 444104, India 2 Department of Plant Pathology, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, Maharashtra 444104, India 3 Nagarjuna Medicinal and Aromatic Plant Garden, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, Maharashtra 444104, India 4 Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre (BARC), Trombay, Mumbai, Maharashtra 400085, India 123 Agric Res https://doi.org/10.1007/s40003-018-0288-8