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MADS29是控制水稻(Oryza sativa L.)种子饱满程度的基因,它通过调控母体组织细胞退化和维持体内激素平衡来影响种子发育.水稻异倍性杂交往往产生败育种子,为了探讨MADS29等种子发育相关基因是否参与其调控,本研究以4份水稻材料(2个二倍体;2个四倍体)构建4个自交组合(对照)和8个杂交组合(正反交),对花粉粒育性、花粉管萌发及伸长、种子发育及MADS29等相关基因表达进行分析.结果表明:(1)异倍性杂交均可正常受精,但杂交种子败育;(2)石蜡切片结果显示,授粉后3 d(3 day after pollination,3 DAP),与对照相比,4n×2n胚乳已进入细胞化时期,但细胞数量较少;而2n×4n胚乳处于合胞体时期,游离核周围未形成细胞壁,胚乳细胞化时期滞后;(3)实时荧光定量PCR(q RT-PCR)表明,6 DAP和8 DAP,MADS29、生长素基因和母体组织细胞程序化死亡(PCD)相关基因的相对表达量在杂交种子中均明显高于对照;淀粉合成基因在杂交种子中的相对表达量显著低于对照.本实验结果表明,在水稻异倍性杂交中,MADS29高表达,生长素基因和母体组织PCD相关基因表达上调,淀粉合成相关基因表达下调,导致胚乳发育异常、种子败育,说明MADS29的高表达导致异倍性杂交种子败育,是一种有别于二倍体水稻种子发育的新型调控方式.
MADS29 is a gene that controls seed fullness in Oryza sativa L. It affects seed development by regulating cell degeneration in maternal tissue and maintaining hormone balance in the body. In aneuploid hybridization of rice, aborted seeds are often produced. In order to investigate the seed development, such as MADS29, In this study, four inbred combinations (control) and eight hybrid combinations (reciprocal) were constructed with 4 rice materials (2 diploids and 2 tetraploids) Fertility, germination and elongation of pollen tube, seed development and expression of MADS29 and other related genes were analyzed.The results showed that: (1) Allohybrids could be fertilized normally, but hybrid seeds were aborted; (2) Compared with the control, 4n × 2n endosperm had entered the cell-forming stage but had fewer cells at 3 days after pollination (3 DAP). However, the 2n × 4n endosperm was in the syncytium-phase with no formation around the free nucleus (3) Real-time quantitative PCR (q RT-PCR) showed that the relative expression levels of 6 DAP and 8 DAP, MADS29, auxin gene and maternal programmed cell death (PCD) In hybrid seeds were significantly higher than the control; The relative expression level of synthetic genes in hybrid seeds was significantly lower than that of the control.The results showed that in rice heterotyphybridization, MADS29 overexpression, auxin gene and the expression of PCD related genes in maternal tissues were up-regulated and the expression of starch-related genes was down-regulated , Resulting in abnormal endosperm development and seed abortion, indicating that high expression of MADS29 results in abortion of heteropolyploid hybrids, which is a new type of regulation that is different from diploid rice seed development.