| Leymus mollis(2n = 4x = 28)is a allotetraploid perennial wild plants in Leymus(Poaceae:Triticeae)and an important genetic resource for wheat improvement.It possesses exceptionally strong rhizomes,large spikes,multiple spikelets,tolerance of abiotic stresses and resistance to various fungal diseases.Chromosome engineering can transfer useful genes from L.mollis into common wheat background,from which can enrich wheat germplasm resources and enhance genetic diversity.In this study,the derivatives of common wheat-L.mollis M39,M11003-4-4-1-1,M11003-3-1-3-3 and M11003-4-4-1-2 were identified by analysis of morphologic,cytological,in situ hybridization(GISH and FISH)analysis,and molecular markers.Results are as follows:(1)Molecular cytogenetic identification of two commom wheat-L.mollis multiple alien addition linesCytological studies demonstrated that M11003-4-4-1-1 had a chromosome karyotype of 2n = 46 with 23 bivalents.GISH analysis was performed on M39 and M11003-4-4-1-1 chromosomes at mitotic metaphase,respectively,with the labeled genomic DNA of L.mollis and P.Huashanica as the probes.Mitotic GISH results showed that the root tip cells of M3 9 had 12 yellow-green signals while M11003-4-4-1-1 contained 4 yellow-green signals,which represented twelve and four exogenous chromosomes from Ns genome of L.mollis,respectively.Using probes Oligo-pSc119.2 and Oligo-pTa535,M39 was proved that it had 42 common wheat chromosomes,2 extra 4B chromosomes and 12 alien chromosomes,while M11003-4-4-1-1 had 2 alien chromosomes and 42 common wheat chromosomes.Molecular makers analysis indicated 19 EST primers,located on wheat homoeologous group 1,2,3,5,6,7 chromosomes could amlify specific L.mollis bands in M39,3 SSR markers,3 EST primers and 2 PLUG primers mapped on homoeologous group 5 and 6 chromosomes could amlify specific L.mollis bands in M11003-4-4-1-1.The plant type of M11003-4-4-1-1 was compact,it was similar to the parent 7182 in spikelet number per spike and awn shape,possed significant differences with 7182 in plant height,spike length,kernels number per spike,the mean plant height was 62 cm,while 1000-grain weight was 45.8 g,superior to the parents.The disease resistance at the adult stage indicated that L.mollis was immune to stripe rust,M39 and M11003-4-4-1-1 exhibited high resistance to stripe rust.In a word,M39 was a wheat-L.mollis multiple alien addition line with Lm#1Ns,Lm#2Ns,Lm#3Ns,Lm#5Ns,Lm#6Ns and Lm#7Ns chromosomes,M11003-4-4-1-1 was a wheat-L.mollis double disomic addition line with Lm#5Ns and Lm#6Ns chromosomes,they showed high resistance to stripe rust.(2)Molecular cytogenetic identification of two commom wheat-L.mollis disomic alien addition linesAccording to the analysis of cytology,M11003-3-1-3-3 and M11003-4-4-1-2 were showed that the configuration was 2n = 44 = 22?.GISH analysis was performed on M11003-3-1-3-3 and M11003-4-4-1-2 chromosomes at mitotic metaphase,respectively,with the labeled genomic DNA of L.mollis and P.Huashanica as the probes.Mitotic GISH results showed that the root tip cells of M11003-3-1-3-3 and M11003-4-4-1-2 had 2 yellow-green signals,respectively,which represented two exogenous chromosomes from Ns genome of L.mollis.Using probes Oligo-pSc 119.2 and Oligo-pTa535,M11003-3-1-3-3 and M11003-4-4-1-2 were proved that they all had a full set chromosomes of common wheat chromosomes and 2 alien chromosomes.Molecular makers analysis indicated 2 EST primers and 5 PLUG primers,located on wheat homoeologous group 7 chromosomes could amlify specific L.mollis bands in M11003-3-1-3-3,1 EST primer and 5 PLUG primers mapped on homoeologous group 5 chromosomes could amlify specific L.mollis bands in M11003-4-4-1-2.There were obvious differences between M11003-3-1-3-3 and M11003-4-4-1-2 in plant height,kernels number per spike,spike length.The disease resistance at the adult stage indicated that M11003-3-1-3-3 exhibited high resistance to stripe rust while M11003-4-4-1-2 was susceptibility to stripe rust.These results showed that M11003-3-1-3-3 was a wheat-L.mollis Lm#7Ns disomic alien addition line,which was highly resistant to stripe rust,M11003-4-4-1-2 was a wheat-L.mollis Lm#5Ns disomic alien addition line.In this study,we identified four wheat-L.mollis alien addition lines,including one multiple alien addition line,one double alien addition line and two disomic alien addition line.Three alien additon lines possed high resistance to wheat stripe rust while the other one was dwarf.They can be used as donors to derive wheat-L.mollis disomic addition lines and translocation lines,in the meanwhile,they can provide germplasm resources for genetic improvement of wheat stripe rust and plant height. |
PDF Full Text Request