Research progress of plant cytogenetics in Jiangsu province.

Cytogenetics was established based on the "Chromosome theory of inheritance", proposed by Boveri and Sutton and evidenced by Morgan's lab in early stage of the 20 th centrary. With rapid development of related research areas, especially molecular genetics, cytogenetics developed from traditional into a new era, molecular cytogenetics in late 1960s. Featured by an established technique named DNA in situ hybridization (ISH), molecular cytogenetics has been applied in various research areas. ISH provids vivid and straightforward figures showing the virtual presence of DNA, RNA or proteins. In combination with genomics and cell biology tools, ISH and derived techniques have been widely used in studies of the origin, evolution, domestication of human, animal and plant, as well as wide hybridization and chromosome engineering. The physical location and order of DNA sequences revealed by ISH enables the detection of chromosomal re-arrangments among related species and gaps of assembled genome sequences. In addition, ISH using RNA or protein probes can reveal the location and quantification of transcripted RNA or translated protein. Since the 1970s, scientists from universities or institutes belonging to the Jiangsu Society of Genetics have initiated cytogenetics researches using various plant species. In recent years, research platforms for molecular cytogenetics have also been well established in Nanjing Agricultural University, Yangzhou University, Nanjing Forestry University, Jiangsu Xuhuai Academy of Agricultural Sciences, and Jiangsu Normal University. The application of molecular cytogenetics in plant evolution, wide hybridization, chromosome engineering, chromosome biology, genomics has been successful. Significant progresses have been achieved, both in basic and applied researches. In this paper, we will review main research progresses of plant cytogenetics in Jiangsu province, and discuss the potential development of this research area.

Inter-simple sequence repeat data reveals high genetic diversity in wild populations of the narrowly distributed endemic Lilium regale in the Minjiang River Valley of China.

Lilium regale E.H. Wilson is endemic to a narrow geographic area in the Minjiang River valley in southwestern China, and is considered an important germplasm for breeding commercially valuable lily varieties, due to its vigorous growth, resistance to diseases and tolerance for low moisture. We analyzed the genetic diversity of eight populations of L. regale sampled across the entire natural distribution range of the species using Inter-Simple Sequence Repeat markers. The genetic diversity (expected heterozygosity= 0.3356) was higher than those reported for other narrowly distributed endemic plants. The levels of inbreeding (Fst = 0.1897) were low, and most of the genetic variability was found to be within (80.91%) than amongpopulations (19.09%). An indirect estimate of historical levels of gene flow (Nm =1.0678) indicated high levels of gene flow among populations. The eight analyzed populations clustered into three genetically distinct groups. Based on these results, we recommend conservation of large populations representing these three genetically distinct groups.

[Efficient plant regeneration in vitro in Pinus massoniana L].

Pinus massoniana L. is one of the important trees for afforestation in South China. The efficient system of plant regeneration from mature zygotic embryos and seedlings of masson pine was established in this study. The influences of basal media, hormones and methods for buds induction, shoots elongation and rooting were studied. The results indicate that DCR medium with 0.5 mg/L BA and 0.05 mg/L IBA shows the highest differentiation rate of adventitious buds. Induction and multiplication of axillary buds take aseptic seedlings as explants. KT has better effect than BA on the axillary buds induction. The best axillary buds induction medium is DCR medium supplemented with 1 mg/L KT and 0.2 mg/L IBA. After culturing on GD medium with 0.1 mg/L BA and 0.2 mg/L IBA for elongation, the buds were transferred on the 1/2 GD medium with 2 mg/L IBA and 0.05 mg/L BA for adventitious roots induction. Paraffin slice indicates that the adventitious buds developed from the meristematic tissue of cotyledonary epicuticula.