Identification Of Long-Distance Transport Signal Molecules And Molecular Markers Development Of Plant Maturity In Tetraploid Potato(Solanum Tuberosum L.)

Potato is the third most important food crop in the world.Maturity is one of major agronomic characters for varieties suitable for different agro-ecological zones.It is critical to explore molecular markers related to early maturtiy and elucidate the molecular mechanismof early maturity trait in development of early potato varieties.In this study,the segregating population of Zhongshu 18 ×Zhongshu 5 was used for molecular marker development and long-distance transport molecules identification.The main results are as follows:1.The results of plant maturity in segregated population fromZhongshu 18 × Zhongshu 5 showed a positive distribution.30 offspring genotypes of extremely early or late maturity were selected respectively for construction the extremely early maturing DNA pool and extremely late maturing DNA pool.Using simplified genome 2b-RAD sequencing,three molecular markers related to maturity(SCARA2-2,SCARA4-21 and SCARA5-16)were developed,which the coincidence rate of early and late maturity reached 96.7% and 90% respectively,and they are valuable for assisting selection in early potato breeding.2.The grafting experiments were conducted to study the effect of rootstock-scion interaction on plant maturity and tuber yield as well as the effect of plant hormone signaling molecules on plant maturity.The results showed that the grafted plants with Zhongshu 5 as the scion and Zhongshu 18 as the rootstock had the same maturity as that of the self-grafted plants of Zhongshu 5,and the grafted plants with Zhongshu 18 as the scion and Zhongshu 5 as the rootstock had the same maturity as that of Zhongshu 18 self-grafted plants.The yield per plant of “Z18 / Z5” grafted plants with Zhongshu 18 as scion was significantly higher than that of “Z5 / Z5” plants grafted with Zhongshu 5 on their own.It was speculated that the maturity of the plants was dominated by the scion varieties.Before physiological maturity,the contents of ABA and SA of stemsegments of grafted plants with Zhongshu 5as scion were higher while the contents of IAA and JA were lower than those with Zhongshu 18 as scion.This indicates that the plant hormones of ABA,SA,IAA and JA are closely related to early maturity of potato.3.Transcriptomics was used to study the long-distance transport mRNA signaling molecules related to plant maturity in grafting experiments.43 long-distance transport mRNA signaling molecules related to early maturity and 292 long-distance transport mRNAs related to late maturity were screened out.It is assumed that the interaction between transcription factors of StCBF1/StCBF2 and StMADS-MC promotes the physiological maturity of potato plants.Above transcription factors may be candidate genes related to early maturity traits.4.Fromthe metabolomics study in the grafting experiments,four metabolites(1-Caffeoylquinic acid,protocatechuic acid-4-glucoside,trihydroxycinnamoylquinic acid,and myricetin-O-glucoside-rhamnoside)signaling molecules related to the potato early maturity were screened,three of which were the phenolic acids with inhibitory effect on plant growth,and the other was flavonoid glycosides that inhibited plant growth by hindering the polar transport auxin IAA.Seven metabolites(L-Histidine,L-Tryptophan,sinapyl alcohol,sinapinaldehyde,cotinine,methoxyindoleacetic acid and DL-Alanyl-DL-phenylalanine)related to the potato late maturity were screened out.