The Regeneration System Establishment Of Immature And Mature Embryos In Aegilpops Tauchii

Aegilops tauschii, the diploid progenitor of the D genome of hexaploid wheat(Triticum aestivum L.), is classified as Aegilops. In this study, the effects of the basal medium, carbon source, transdifferentiation time, and plant auxins including 2,4-Dichlorophenoxyacetic acid(2,4-D) and Kinetin(KT), 6-Benzyladenin(6-BA) and Indole-3-acetic acid(IAA) on callus induction and plant regeneration from Ae.tauschii immature embryo(IEs) and mature embryo(MEs) culture were investigated. The objective of this study was to establish the IEs and MEs regeneration system for Ae.tauschii, which will facilitate genetic transformation of D genome to study the gene functions of common wheat. The results are as follows:1. The effects of basal medium, carbon source and 2,4-D on induction of IEs callus in Ae.tauschii were studied. The results showed that frequency of callus induction(CIF)performed significant differences among basal medium, and the highest CIF was induced in MS basal medium. However, the effect of concentration of 2,4-D on callus induction of IEs had no significant difference and the average CIF was between 83.41% and 94.38%. The basal medium and concentration of 2,4-D had a significant effect on frequency of embryogenic callus(ECF). The highest ECF was also induced in MS basal medium and average frequency of embryogenic callus was 74.41%. The medium supplemented with 2.0mg ï¹’ L-1 2,4-D led to the induction of most high-quality embryogenic calli with pale,smooth, and compact nodules, with average ECF of 75.26%. The differences of the effects of carbon source on callus induction and embryogenic callus induction of IEs were not significant and 30 gï¹’L-1 sucrose was optimal in practice.2. The effects of basal medium, carbon source, 2,4-D and KT on differentiation of IEs callus in Ae.tauschii were studied. The results showed that the basal medium, concentration of 2,4-D and carbon source had no significant effect on frequency of differentiated callus(DCF). However, KT played important roles in IEs callus differentiation and plant regeneration. The optimal concentration of KT in the medium was 1.0 mgï¹’L-1and average DCF was 64.44%. Overall, callus induction medium of MS + 3.0 mgï¹’L-1 2,4-D + 15 gï¹’L-1sucrose + 15 gï¹’L-1mannitol and callus differentiation medium of MS + 1.0 mgï¹’L-1KT + 15 gï¹’L-1 sucrose + 15 gï¹’L-1 mannitol was optimal for IEs callus induction and plant regeneration of Ae.tauschii.3. The effects of transdifferentiation time, 2,4-D, KT, ratio of 6-BA and IAA on induction and differentiation of MEs callus in Ae.tauschii were studied. The results showed that concentration of 2,4-D had a significant effect on CIF, ECF, DCF and frequency of regenerated plants(RPF). With the increase of 2,4-D concentration, these four indicators showed the tendency of reducing after the increasing. When the concentration of 2,4-D was added to 2.0 mg ï¹’ L-1, these four indicators achieved the maximum 62.17%, 39.96%,49.45% and 4.20%, respectively. However, transdifferentiation time had no significant effect on DCF and RPF. From one point of the quality of callus, 25 days and 30 days of transdifferentiation time gave higher quality of callus than those with 35 days and 40 days of transdifferentiation time.4. KT played important roles in the rate of differentiated callus and regenerated plants of MEs. With the increase of KT concentration, DCF and RPF showed the tendency of reducing after the increasing. When the concentration of KT was 2.0 mg ï¹’ L-1, these indicators reached the maximum, 64.44% and 2.22%, respectively. The performance of MEs culture with 6-BA and IAA combination was that: when the concentration of IAA was0.25 mgï¹’L-1, with the increase of 6-BA concentration, DCF and RPF of MEs showed the tendency of reducing after increasing and DCF and RPF reached the maximum, 70.03% and6.35%, respectively, with the 6-BA concentration at 2.0 mgï¹’L-1. When the concentration of6-BA was 1.0 mgï¹’L-1, with the increase of IAA concentration, DCF and RPF of ME also showed the tendency of reducing after increasing and DCF and RPF achieved the maximum,64.80% and 5.56%, respectively, with the IAA concentration at 0.25mgï¹’L-1.