title: Heat stress yields a unique MADS box transcription factor in determining seed size and thermal sensitivity.
abstract: Early seed development events are highly sensitive to increased temperature. This high sensitivity to a short-duration temperature spike reduces seed viability and seed size at maturity. The molecular basis of heat stress sensitivity during early seed development is not known. We selected rice (Oryza sativa), a highly heat-sensitive species, to explore this phenomenon. Here, we elucidate the molecular pathways that contribute to the heat sensitivity of a critical developmental window during which the endosperm transitions from syncytium to the cellularization stage in young seeds. A transcriptomic comparison of seeds exposed to moderate (35°C) and severe (39°C) heat stress with control (28°C) seeds identified a set of putative imprinted genes, which were down-regulated under severe heat stress. Several type I MADS box genes specifically expressed during the syncytial stage were differentially regulated under moderate and severe heat stress. The suppression and overaccumulation of these genes are associated with precocious and delayed cellularization under moderate and severe stress, respectively. We show that modulating the expression of OsMADS87, one of the heat-sensitive, imprinted genes associated with syncytial stage endosperm, regulates rice seed size. Transgenic seeds deficient in OsMADS87 exhibit accelerated endosperm cellularization. These seeds also have lower sensitivity to a moderate heat stress in terms of seed size reduction compared with seeds from wild-type plants and plants overexpressing OsMADS87 Our findings suggest that OsMADS87 and several other genes identified in this study could be potential targets for improving the thermal resilience of rice during reproductive development.
authors.affiliation: Department of Agronomy and Horticulture (C.C., K.B., J.J.F., Z.W., H.W.) and School of Biological Sciences (K.L., C.Z.), University of Nebraska, Lincoln, Nebraska 68583; andKey Laboratory of Crop Genetics and Physiology of Jiangsu Province and Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou 225009, China (C.C.).
authors.forename: Chen
authors.identifier: 0000-0002-9748-3111
authors.initials: C
authors.lastname: Chen
authors.affiliation: Department of Agronomy and Horticulture (C.C., K.B., J.J.F., Z.W., H.W.) and School of Biological Sciences (K.L., C.Z.), University of Nebraska, Lincoln, Nebraska 68583; andKey Laboratory of Crop Genetics and Physiology of Jiangsu Province and Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou 225009, China (C.C.).
authors.forename: Kevin
authors.initials: K
authors.lastname: Begcy
authors.affiliation: Department of Agronomy and Horticulture (C.C., K.B., J.J.F., Z.W., H.W.) and School of Biological Sciences (K.L., C.Z.), University of Nebraska, Lincoln, Nebraska 68583; andKey Laboratory of Crop Genetics and Physiology of Jiangsu Province and Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou 225009, China (C.C.).
authors.forename: Kan
authors.initials: K
authors.lastname: Liu
authors.affiliation: Department of Agronomy and Horticulture (C.C., K.B., J.J.F., Z.W., H.W.) and School of Biological Sciences (K.L., C.Z.), University of Nebraska, Lincoln, Nebraska 68583; andKey Laboratory of Crop Genetics and Physiology of Jiangsu Province and Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou 225009, China (C.C.).
authors.forename: Jing J
authors.identifier: 0000-0002-5420-7387
authors.initials: JJ
authors.lastname: Folsom
authors.affiliation: Department of Agronomy and Horticulture (C.C., K.B., J.J.F., Z.W., H.W.) and School of Biological Sciences (K.L., C.Z.), University of Nebraska, Lincoln, Nebraska 68583; andKey Laboratory of Crop Genetics and Physiology of Jiangsu Province and Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou 225009, China (C.C.).
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Agronomy and Horticulture (C.C., K.B., J.J.F., Z.W., H.W.) and School of Biological Sciences (K.L., C.Z.), University of Nebraska, Lincoln, Nebraska 68583; andKey Laboratory of Crop Genetics and Physiology of Jiangsu Province and Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou 225009, China (C.C.).
authors.forename: Chi
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Agronomy and Horticulture (C.C., K.B., J.J.F., Z.W., H.W.) and School of Biological Sciences (K.L., C.Z.), University of Nebraska, Lincoln, Nebraska 68583; andKey Laboratory of Crop Genetics and Physiology of Jiangsu Province and Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou 225009, China (C.C.) hwalia2@unl.edu.
authors.forename: Harkamal
authors.identifier: 0000-0002-9712-5824
authors.initials: H
authors.lastname: Walia
mesh_terms: D002453:Cell Cycle / Q000502:physiology; D004251:DNA Transposable Elements; D056625:Endosperm / Q000033:anatomy & histology / Q000166:cytology / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D018392:Genomic Imprinting; D018869:Heat-Shock Response / Q000502:physiology*; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism*; D012275:Oryza / Q000502:physiology*; D059828:Plant Cells / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D012639:Seeds / Q000033:anatomy & histology / Q000502:physiology*
chemical_list: D004251:DNA Transposable Elements; D026161:MADS Domain Proteins; D010940:Plant Proteins