Transient expression of a TaGRF4-TaGIF1 complex stimulates wheat regeneration and improves genome editing

Science China Life Sciences - Genome editing is an unprecedented technological breakthrough but low plant regeneration frequencies and genotype dependence hinder its implementation for crop...     

PCR-DGGE detection of the bacterial community structure in the Inner Mongolia steppe with two different DNA extraction methods

Compared with conventional methods, molecular biological technique, such as PCR-DGGE (denaturing gradient gel electrophoresis), is informative in examining the structure of the soil bacterial community through the extraction of microbial DNA from soil and generation of bacterial community profiles by PCR amplification of 16S rRNA genes. Extraction efficiency of soil microbial DNA is the most important step in these methods. At present, the frozen-thawing method and bead-beating method are most widely used in genomic extraction. Nevertheless, comparison of these two methods has not been conducted in different soil types, especially in humus-rich soil. In this study, extraction efficiencies of the two methods were compared in humus-rich steppe soil in Inner Mongolia based on the PCR-DGGE analysis of bacterial community structure. The results indicated that the bead-beating method is better than the frozen-thawing method in genomic DNA extraction efficiency. In addition, 21 bands in the DGGE pattern with the bead-beating method were further selected, cloned and sequenced. Based on similarity matching, all the sequences formed five major clusters: Actinobacteria; α-, β-, γ-, Proteobacteria ; Bacteriodetes ; Gemmatimonadetes and Acidobacteria . Of the 21 clones obtained from DGGE patterns, YC4 showed 99.7% similarity to Pseudomonas sp. (DQ339153); YC5, YC18 and YC19 showed 99.9 % similarity to Gram-positive bacterium (AB008510), Virgisporangium ochraceum (AB006162) and Micromonospora chalcea (X92613), respectively.     

Rapid in vitro multiplication and ex vitro rooting of Malus zumi (Matsumura) Rehd

Micropropagation system of Malus zumi was optimized by studying the influence of plant growth regulators and culture conditions. The axillary buds were used for mutiplication of in vitro shoot culture on agar Murashige and Skoog (1962) (MS) medium with combination of 1 mg l⁻¹ BAP, 0.5 mg l⁻¹ NAA or 0.5 mg l⁻¹ IAA or 0.5 mg l⁻¹ IBA under 16 h photoperiod. The shoot growth in culture was not significantly affected within a broad range (5.0–7.0) of initial medium pH. The highest shoot (13) was obtained on medium containing 1.0 mg l⁻¹ BAP and 0.5 mg l⁻¹ IAA. Well-developed shoots, 35–50 mm in length, were successfully rooted ex vitro at 86.3% by a 2-h-treatment with aqueous solution containing MS salts and 100 mg l⁻¹ IBA prior to their planting in growing substrate composed of soil and vermiculite (1:1 v/v). The survival rate of transplantation reached 88.0% when transferred to field condition.     

植物液泡膜阳离子/H+反向转运蛋白结构和功能研究进展

阳离子转运蛋白在调节细胞质阳离子浓度过程中发挥关键作用。液泡是一个储存多种离子的重要细胞器,阳离子 (Ca2+)/H+反向转运蛋白CAXs定位在液泡膜上,主要参与Ca2+向液泡的转运,也参与其他阳离子的转运。近年来,植物中分离鉴定了多个CAX基因,植物CAXs主要有4个功能域：NRR通过自抑制机制调节Ca2+转运活性,CaD和C功能域分别赋予CAXs的Ca2+和Mn2+专一性转运活性,D功能域可调节细胞质pH。拟南芥AtCAXs参与植物的生长发育和胁迫适应过程,AtCAX3主要在盐胁迫下转运Ca2+,At