ISSR Polymorphism Analysis of Eight F_1 Hybrids of Erianthus fulvus and Saccharum spp.

In this study, twelve primers were used for ISSR （ inter simple sequence repeat） analysis of eight F1 hybrids of Erianthu.sfulvus and sugarcane （ Saccha- rum spp. ）. The results showed that totally 133 bands were amplified, including 111 polymorphic bands, showing a polymorphic rate of 83.46%, which indicated that there are abundant genetic variations among F1 progenies derived from crossing between cultivated sugarcane and E. fu/vus. The average genetic similarity coef- ficients between F1 progenies and female parent Yacheng 89-9, F1 progenies and male parent E. fidvas were 0.67 and 0.44, respectively. UPGMA clustering result of F1 progenies showed that all the progenies were clustered with female parent, suggesting that the genetic material of female parent was predominated in F： proge- nies, which also revealed that the chromosome number of F, progenies was not directly related to the clustering results based on ISSR analysis.

Chromosomal Transmission in F_2BC_1Hybrid Progenies between Sugarcane and Erianthus fulvus

[ Objective ] This study aimed to provide a scientific basis for breeding new sugarcane varieties with hybrid progenies of Erianthus fulvus and modifying existing sugarcane cultivars. [ Method] Chromosomal slides of the F2 and F2 BC1 hybrid progenies between sugarcane and E. fu/vus （2n = 20） and those of parental materials were prepared with the wall degradation hypotonic method, to further analyze the chromosomal transmission in the F2 and F2BC1 hybrid progenies and to investigate the chromosome transmission mechanism. [ Result ] The results showed that, somatic chromosome number varied in various hybrid progenies; chromo- somes from parents were transmitted into the somatic cells of F2 hybrids in ＂2n ＋ n＂ pattern and transmitted into the somatic cells of F2BC1 hybrids in ＂n ＋ n＂ pattern. [ Conclusion ] This study provided a preliminary cytological basis for further use of these materials in sugarcane breeding.

Karyotype Analysis of BC_1 and BC_2 Progenies between Sugarcane and Erianthus fulvus

In this study, karyotype analysis of F2BCl progenies between sugarcane （Saccharum spp. ） and Erianthusfulvus was conducted. The result showed that most chromosomes of YAU04/14, YAU09/02, YAU09/05, YAU09/26 and YAU09/52 are median region （m） chromosomes, while only a small amount of chromosomes are submedian （sin） chromosomes and median point （M） chromosomes. The karyotype formulae of five experimental materials are 2n = 106 = 98m ＋ 8sm, 2n = 106 - 2M ＋ 104m, 2n = 106 = 4M ＋ 96m ＋ 6sin, 2n = 102 = 2M ＋ 92m ＋ 8sin and 2n = 106 = 4M ＋ 96m ＋ 6sin, respectively. The karyotypes of all materials belong to symmetrical 2B type, indicating that the chromosomes of progenies are primitive.

Karyotype Comparison of F_1 and F_2 Hybrids of Sugarcane and Erianthus fulvus

Chromosome specimens of sugarcane, Erianthus fu/vus and their progenies were prepared with wall degradation hypotonic method to analyze the karyotypes of parents and Fl, F2 hybrids. The results showed that most chromosomes of experimental materials are median region （m） chromosomes, while only a small amount of chromosomes are submedian （sm） chromosomes. The karyotype of YAU04/102 belongs to 2C type, while other materials belong to 2B type. In addition, the karyotypes of hybrids are asymmetrical and the chromosomes of hybrids show an evolutionary trend compared with parental chromosomes.

A chromosome-level genome assembly for Erianthus fulvus provides insights into its biofuel potential and facilitates breeding for improvement of sugarcane

Erianthus produces substantial biomass,exhibits a good Brix value,and shows wide environmental adaptability,making it a potential biofuel plant.In contrast to closely related sorghum and sugarcane,Erianthus can grow in degraded soils,thus releasing pressure on agricultural lands used for biofuel production.However,the lack of genomic resources for Erianthus hinders its genetic improvement,thus limiting its potential for biofuel production.In the present study,we generated a chromosome-scale reference genome for Erianthus fulvus Nees.The genome size estimated by flow cytometry was 937 Mb,and the assembled genome size was 902 Mb,covering 96.26%of the estimated genome size.A total of 35065 proteincoding genes were predicted,and 67.89%of the genome was found to be repetitive.A recent wholegenome duplication occurred approximately 74.10 million years ago in the E.fulvus genome.Phylogenetic analysis showed that E.fulvus is evolutionarily closer to S.spontaneum and diverged after S.bicolor.Three of the 10 chromosomes of E.fulvus formed through rearrangements of ancestral chromosomes.Phylogenetic reconstruction of the Saccharum complex revealed a polyphyletic origin of the complex and a sister relationship of E.fulvus with Saccharum sp.,excluding S.arundinaceum.On the basis of the four amino acid residues that provide substrate specificity,the E.fulvus SWEET proteins were classified as monoand disaccharide sugar transporters.Ortho-QTL genes identified for 10 biofuel-related traits may aid in the rapid screening of E.fulvus populations to enhance breeding programs for improved biofuel production.The results of this study provide valuable insights for breeding programs aimed at improving biofuel production in E.fulvus and enhancing sugarcane introgression programs.

甘蔗赤腐病内生拮抗菌YC89的筛选及鉴定

【目的】筛选防治甘蔗赤腐病(sugarcane red rot)的生防菌株。【方法】实验以前期分离获得的甘蔗内生细菌为目标菌,以甘蔗赤腐病的病原真菌镰孢炭疽菌(Colletotrichum falcatum Went.)为指示菌,采用平板对峙法筛选对该病菌有较强抑制作用的菌株,然后通过琼脂扩散法测定菌株代谢产物对抑菌活性的影响,并对具有较好拮抗效果的高效菌株进行抑菌广谱性分析并对其进行鉴定。最后通过形态学、生理生化特征以及16S rDNA和gyrA序列分析对高效菌株YC89进行鉴定。【结果】经初筛筛选到抑菌带均大于1.60 cm的5株拮抗细菌,其中X22、W2、YC89抑菌带均高达1.87 cm。对初筛得到的5株内生菌进行复筛,结果所示菌株YC89、H1、X22、W2、YT93对镰孢炭疽菌的抑菌率都在75%以上,其中菌株YC89对该病菌的抑菌效果最好,其抑菌率为78%。菌株YC89的发酵液、上清液、过滤液及粗蛋白提取液对镰孢炭疽菌的生长有较强的抑制作用,且菌株YC89对玉米大斑病、甘蔗梢腐病、草莓灰霉病等7种病原菌也有较好的抑制效果。通过菌株鉴定结果,初步将YC89菌株鉴定为贝莱斯芽孢杆菌(Bacillus velezensis)。【结论】菌株YC89对镰孢炭疽菌具有较好的抑制效果,表明其对甘蔗赤腐病的生物防治具有较大的应用潜力。