Too little, too late: transcription during imbibition of lethally aged soybean seeds is weak and delayed, but not aberrant

Abstract

O_TBL View this table: org.highwire.dtl.DTLVardef@116f1e7org.highwire.dtl.DTLVardef@163aa97org.highwire.dtl.DTLVardef@54d174org.highwire.dtl.DTLVardef@8342f3org.highwire.dtl.DTLVardef@1a08df1_HPS_FORMAT_FIGEXP M_TBL C_TBL O_LIThis study investigates alive to dead signals in seeds that aged during cool, dry storage. Signals may invoke abrupt, lethal metabolic pathways or reflect effects of accumulated small injuries which impair recovery from life in the dry state. C_LIO_LICohorts of soybean (Glycine max cv. Williams 82) seeds were stored for 3, 19 and 22 years. Transcriptomes of dry embryonic axes and axes 24 hours after imbibition (HAI) were sequenced to determine gene expression patterns. These cohorts showed about <2, 40, and ~99% mortality, respectively, in response to storage and aging. C_LIO_LIA total of 19,340 genes were significantly differentially expressed (SDE) in imbibed axes compared to dry axes. Gene expression patterns of imbibed axes clustered into three groups that represented high, low, and no germination potential (GP). There were 17,360 SDE genes in high-GP axes and 4,892 SDE genes, mostly upregulated, in no-GP axes. Transcriptomes of no-GP axes were similar to healthy axes at 3 HAI. C_LIO_LISlow transcription, not transcription errors or novel expression pathways, portends failure to transition from seed to seedling. We conclude that the signature of death in dry aged seeds arises from metabolism that is "too little and too late." C_LI