De novo assembly of the seed transcriptome and search for potential EST-SSR markers for an endangered, economically important tree species: Elaeagnus mollis Diels

Seeds of Elaeagnus mollis(Elaeagnaceae) produce an edible oil and contain more vitamin E(Ve) than major oil-seed crops. Despite its economic value, there is no information on its genome sequence. Here, we used the Illumina platform to determine the seed transcriptome of E.mollis to identify the genes related to Ve biosynthesis and potential simple sequence repeat(SSR) markers. In total, 100,999 unigenes were obtained with an average length of 605 bp and N50 of 985 bp. Of these unigenes,52,256(51.7%) were annotated in at least one public database(NT, NR, PFAM, Swiss Prot, KOG, KO, and GO)in searches using blastn/x. The unigene annotation identified 15 unigenes encoding six enzymes(GGR, HPPD,HPT/VTE2, MPBQ-MT/VTE3, TC/VTE1, and c-TMT/VTE4) putatively involved in Ve biosynthesis. In addition,16,810 SSRs distributed in 14,057 unigenes were mined.Of these, 2820, 583, and 3423 SSRs were located in the 50–UTR, coding sequence(CDS), and 30–UTR regions,respectively, while the remaining 9984 SSRs had undetermined physical locations. The largest group of repeat motifs comprised mononucleotide repeats(70.76%), followed by dinucleotide(15.59%) and trinucleotide(12.10%)repeats. AG/CT(8.69%) and AAG/CTT(4.15%) were the main dinucleotide and trinucleotide repeats, respectively.Furthermore, 9597 SSR-specific primer pairs were designed. Among 100 primer pairs selected randomly to determine their usefulness, 53 proved to be efficient. To the our best of knowledge, this work is the first study of the E. mollis transcriptome and constitutes valuable genomics data for future genetic engineering studies to alter the amount of Ve. The identified potential EST-SSR markers can be used for population genetics studies and assistedbreeding of E. mollis.

Species and Functions of Rhizobia Growing on Trees and Colonization Mechanisms

The current research progress in China shows that the tree species of rhizobia that have been found are mainly trees of 11 genera in Papilionaceae,Elaeagnaceae and Mimosaceae,and the rhizobia are mainlyα-rhizobia,which come from multiple genera.Temperature,pH value,NaCl content and antibiotics all affect the growth of tree rhizobia;and different species of rhizobia have different stress resistance,which is related to their living environment.Rhizobium inoculation can promote plant height,biomass,root-to-shoot ratio,and root architecture of trees.We discussed and analyzed the development history and application status of rhizobia research,and prospected their future development directions.In the future,tree rhizobia will surely be used as a means of production to promote efficient agricultural production and sustainable agricultural systems.

沙棘主要害虫发生规律及防治

沙棘属于胡颓子科（Elaeagnaceae）沙棘属（Hippophae）植物,又名醋柳、酸刺和黑刺,落叶灌木或小乔木,耐寒、耐旱、抗盐碱、抗风沙,对土壤要求不太严格,适应性强,是防风固沙、保持水土流失,快速恢复植被的先锋树种,尤其是开发建设、环境污染、植被破环严重的地区,发展沙棘具有良好的生态、社会、经济等方面的多重效益。

适宜甘肃酒泉栽培的大沙枣品种筛选

大沙枣又名大果沙枣（Elaeagnus moorcroftii Waill.）,为胡颓子科（Elaeagnaceae）沙枣属多年生落叶乔木,是绿洲内营造防风固沙林、农田防护林以及荒滩造林的主要乡土树种。大沙枣适应性强、耐干旱,防风固沙作用大,成为造林的重要树种;其产量高,而且有很高的使用价值,除鲜食之外,花、果、枝、叶等均可入药,也是优良的经济树种。