| As the initial stage of rice growth and development,seed germination determines the time when rice enters the natural and agricultural ecosystems,thus affecting the survival and yield of rice.Therefore,the success of seed germination plays a decisive role in the reproduction and survival of rice offspring.Rice seed germination is a very complicated process,which is regulated by many factors.ABA,one of the plant hormones,inhibits rice seed germination.Previous study of PLA3(PLASTOCHRON3)found by genetic screening rice mutant material of PLA3 gene.The mutant was short,vivoparious,reducing ABA content than wild type during young sprout period.In order to study the relationship between PLA3 and ABA regulation of seed germination,the CRISPR/Cas9 technique was used to knockout PLA3 genes in Nipponbare.Taking pla3-C and wild type as study materials,we explore the relationship of PLA3 and ABA in regulation of seed germination through comparing the difference of germination,the difference of the ABA content,and the difference of gene expression of ABA.Here are the main results:1.The effect of PLA3 gene on seed germination: the mutant was short,vivoparious,and highly sterile,compared with the wild type;the embryo of pla3-C has a large proportion in the seed,while the endosperm has a small proportion.Most materials of pla3-C die after a week of imbibition,only few of them survive;pla3-C has short roots and a small number of roots;By germination experiment,it was found that the germination of pla3-C seeds began at 8h of imbibition,most of the seeds were completed germination at 24 h of imbibition,while the germination of wild-type seeds began at 16 h,and completed at 36 h.Thus the germination of pla3-C was easier than that of wild-type.2.Relationship between PLA3 gene and ABA: the ABA content of pla3-C was lower than that of wild type by detection ABA of LC-MS/MS during seed germination;while treated with 5μM ABA,the rate of germination was unchanged of pla3-C;the expression of PLA3 in wild-type rice under ABA treatment was higher than that in wild-type rice under distilled water treatment.Thus,ABA increased the expression of PLA3,and PLA3 influence ABA content.3.Relationship between PLA3 and ABA metabolism-related genes: the expression level of genes in pla3-C and wild type was determined by qPCR,and it was found that theexpression level of ABA catabolic gene OsABA8ox-1 was up-regulated in pla3-C,while the expression level of ABA synthetic gene OsABA2 was little changed.PLA3 regulates the decomposition of ABA by inhibiting the expression of OsABA8ox-1,so that the rate of ABA synthesis is much lower than that of ABA catabolism.4.The relationship between PLA3 and ABA signaling pathway: the expression of OsPP2C51 gene in pla3-C,a negative regulator of ABA signaling pathway,was up-regulated by qPCR.It is speculated that PLA3 can inhibit ABA signaling pathway by inhibiting the expression of OsPP2C51,and resulting seeds easy to germinate.The expression of ABA receptor OsPYL5 in pla3-C was up-regulated under distilled water treatment,while the expression of OsPYL5 in pla3-C was down-regulated under 5μM ABA treatment.It is speculated that because of the reduced ABA content in pla3-C,in order to maintain the ABA signaling pathway,the expression of the ABA receptor OsPYL5 gene was up-regulated to express more OsPYL5 and thus bind to the low-concentration ABA. |
PDF Full Text Request