Ming-Chung Liu and Der-Ming Yeh
Jianfeng Liu, Bowen Yang, Yuetong Ming, Yuchu Zhang and Yunqing Cheng
Rubus idaeus has remarkable economic and cultural value. Developing efficient simple sequence repeat (SSR) markers is necessary for the molecular breeding of red raspberry. In this study, SSR mining was performed using the de novo transcriptome sequence of R. idaeus. In total, 14,210 SSR sequences were identified from 11,158 SSR-containing unigenes. In all the SSR sequences, mononucleotide, dinucleotide, and trinucleotide repeats were the most common, and their number and percentage were 1323 (9.31%), 6752 (47.52%), and 4897 (34.46%), respectively. Of the mononucleotide and dinucleotide repeats, A/T, AG/CT, AT/AT, and AC/GT were more abundant and accounted for 9.09%, 37.82%, 6.51%, and 3.14% of the total repeat number, respectively. In the trinucleotide, tetranucleotide, pentanucleotide, and hexanucleotide repeats, the nucleotide (NT) patterns AAG/CTT, AAAG/CTTT, AAAAG/CTTTT, and AAGAGG/CCTCTT were the most frequent, and accounted for 14.11%, 0.38%, 0.57%, and 0.23% of the total SSRs, respectively. Of the 480 SSR-containing unigenes with gene ontology (GO) annotation, the classification results showed that they were mainly involved in binding, catalytic, and transporter molecular functions. Most of the 3441 SSR-containing unigenes with the Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation were involved in the following top five pathways: metabolic, RNA transport, spliceosome, protein processing in the endoplasmic reticulum, and mRNA surveillance. Thirty pairs of primers derived from the red raspberry transcriptome were randomly selected to assess their polymorphism by using 15 red raspberry germplasms, in which the polymorphism information content (PIC) values ranged from 0.50 to 0.86, with a mean of 0.73, thereby indicating a high level of polymorphism. The unweighted pair group method with arithmetic mean clustering results indicated that the thirty pairs of primers could precisely distinguish the germplasms. This study reveals the SSR distribution characteristics of red raspberry and provides a scientific basis for further genetic diversity studies and genetic linkage map construction for this species.
Junne-Jih Chen, Ming-Chung Liu and Yang-Hsiu Ho
Tuber production of calla lily (Zantedeschia elliottiana Spreng cv. Super Gold) was investigated using three size ranges (7-10, 4-7, and <4 mm shoot diameter) of in vitro plantlets acclimated in either pots or soil beds in a protected house. The shoots and tubers of large plantlets exhibited higher rates of dry-matter accumulation than did those of small plantlets. The diameter of tubers harvested from pots ranged from 0.67 to 4.1 cm with median values of 2.7, 2.1, and 1.9 cm for the plants derived from large, medium, and small plantlets, respectively. Plants grown in soil beds, regardless of size, produced larger tubers than did those grown in pots. Tubers >3 cm in diameter developed on 25% and 52% of plants grown in pots and soil beds, respectively. Our results suggest that improved calla lily production could be realized by using larger in vitro plantlets as the source material and growing them in soil beds in a protected house.
Boling Liu, Hongzhou Fang, Chaorong Meng, Ming Chen, Qingdong Chai, Kai Zhang and Shijuan Liu
In the present study, the effect of plant growth regulators (PGRs) on callus regeneration, adventitious shoot differentiation, and root formation of Haworthia turgida Haw. was investigated. The greatest callus induction percentage (95.6%) was achieved with leaf explants inoculated on Murashige and Skoog (MS) medium with 1.0 mg·L−1 6-benzyladenine (BA) and 0.1 mg·L−1 1-naphthaleneacetic acid (NAA), and this callus induction medium supplemented with 2.5 mg·L−1 thidiazuron (TDZ) was optimal for callus proliferation. The maximum number of shoots (25.7) was obtained when the callus was cultured on MS medium supplemented with 1.0 mg·L−1 BA and 0.2 mg·L−1 2,4-dichlorophenoxyacetic acid (2,4-D). The highest number of roots per shoot (6.2) and highest rooting frequency (82.0%) were obtained when adventitious shoots were inoculated on MS medium with 0.05 mg·L−1 NAA. Regenerated plantlets were transferred to a mixture of vermiculite and soil and acclimated in a greenhouse. The survival rate of the transplanted plantlets was about 91.6%. The rate of ex vitro rooting was 83.3%, indicating that this technique is effective for root induction in H. turgida. This study has established a rapid and efficient micropropagation system that can be beneficial for commercial cultivation and germplasm conservation of H. turgida.
Jun-Bo Yang, Hong-Tao Li, De-Zhu Li, Jie Liu, Lian-Ming Gao, De-Zhu Li, Lian-Ming Gao and Jie Liu
The Himalayan yew, Taxus wallichiana Zucc., is an endangered species with a scatted distribution in the Eastern Himalayas and southwestern China. In the present study, 10 microsatellite markers from the genome of T. wallichiana were developed using the protocol of fast isolation by amplified fragment length polymorphism of sequences containing repeats (FIASCO). Polymorphism of each locus was assessed in 28 samples from four wild populations of the Himalayan yew. The allele number of the microsatellites ranged from two to five with an average of 2.9 per allele. The observed and expected heterozygosity varied from 0.00 to 1.00 and from 0.3818 to 0.7552, respectively. Cross-species amplification in another two yew species showed eight of them holding promise for sister species. Two of the 10 loci (TG126 and TC49) significantly deviated from Hardy-Weinberg expectations. No significant linkage disequilibrium was detected between the comparisons of these loci. These polymorphic microsatellite markers would be useful tools for population genetics studies and assessing genetic variations to establish conservation strategy of this endangered species.
Hai-nan Liu, Jian-rong Feng, Xiao-fang Liu, Wen-hui Li, Wen-juan Lv and Ming Luo
Three kinds of expression vectors of a pollen-S determinant were constructed to provide a reference for molecular breeding of self-compatible (SC) Prunus species. An S-haplotype-specific F-box (SFB) protein gene from the ‘Xiaobaixing’ apricot (Prunus armeniaca) was cloned by reverse transcription polymerase chain reaction (RT-PCR) and 3′-rapid-amplification of cDNA ends (3′-RACE). A 1136-bp sequence complementary to the 3′-end of the cDNA (GenBank accession number KP938528.2) with a 912-bp complete open reading frame (ORF) was obtained. The deduced amino acid sequence contained an F-box domain, two variable regions, and two hypervariable regions with structural characteristics similar to SFB in other Rosaceae plants. Sense, antisense, and RNA interference (RNAi) vectors for SFB were constructed by enzyme restriction. The target fragment was restricted using the corresponding restriction enzyme and then directionally inserted between the 35S cauliflower mosaic virus promoter and the nopaline synthase terminator (NOS-ter) of the expression vector pCAMBIA-35S-MCS-NOS-NPTII. The intron-containing hairpin RNA (ihpRNA) was obtained by fusion PCR. The constructed vectors were transferred into Agrobacterium tumefaciens strain LBA4404 by freezing/thawing. The RNAi vector of SFB was also transformed in tobacco (Nicotiana tabacum). The successful construction of these three expression vectors provides a basis for transforming ‘Xiaobaixing’ apricot and the breeding of SC Prunus cultivars.
Ming Liu, Aijun Zhang, Xiaoguang Chen, Rong Jin, Hongmin Li and Zhonghou Tang
Potassium (K+) is an essential nutrient element for the growth and development of sweetpotato [Ipomoea batatas (L.) Lam.]. To investigate growth and physiological responses to K+ deficiency during early growth stage of sweetpotato, two representative cultivars with different tolerance to K+ deficiency were chosen. The seedlings of ‘Xushu 32’ (tolerance to K+ deficiency) and ‘Ningzishu 1’ (sensitive to K+ deficiency) were cultured in three different K+ concentrations (K0: 0 mmol·L−1 K+; K1: 5 mmol·L−1 K+; and K2: 20 mmol·L−1 K+, the control) of nutrient solution. Results showed that the extreme K+ deficiency (K0) significantly reduced the total dry weight, leaf number, root length, and chlorophyll content (CCI) compared with K2. However, the growth traits of ‘Xushu 32’ were less suppressed than those of ‘Ningzishu 1’. The net photosynthetic rate (P n), stomatal conductance (g S), and transpiration rate (T r) of ‘Ningzishu 1’ were significantly decreased in K0 and K1 (low K+), whereas ‘Xushu 32’ showed no significant change in K1 treatment. Increasing minimal fluorensence (F 0) of ‘Ningzishu 1’ comes with decreased maximum quantum efficiency of photosystem II (PSII) photochemistry (F v/F m) and photochemical quenching (q P) at K0 treatment. However, all the chlorophyll fluorescence parameters in ‘Xushu 32’ were nonsignificantly changed by K+ deficiency (K0 and K1). These results suggest that ‘Xushu 32’ could maintain a better growth state to adapt to K+ deficiency stress, which may be mainly because of a lighter affected photosynthesis and a less damaged PSII reaction center.
Yansheng Li, Ming Du, Qiuying Zhang, Guanghua Wang, Jian Jin, Stephen Herbert and Xiaobing Liu
Planting date influences grain soybean yield and quality, but no information is available regarding the responses of seed chemical compositions to delayed planting date in vegetable soybean [Glycine max (L.) Merr.]. Three vegetable soybean cultivars, CAS No.1, Tai 292, and 121, were planted on 3 May, 15 May, 27 May, and 8 June in the field during the 2010 and 2011 growing seasons. The experiment was a randomized complete block design with three replications on a typical Mollisol (black soil). We found that late planting reduced fresh pod yield in all cultivars and years. The reduction in fresh pod yield to delayed planting was significantly correlated with the reduction in the number of two-seed pods per plant. Cultivars with strong capacity in retaining more two-seed pods may possess an advantage if planting is delayed. Planting after 15 May increased seed protein content by 4.1% to 7.5% and reduced oil content by 2.4% to 26.3% for different cultivars. The contents of free amino acid, sum of fructose and glucose, raffinose, and stachyose in seed were also increased by late planting. By contrast, late planting reduced the seed sucrose content ranging from 7.6% to 45.5% for the different cultivars. Planting on 3 May usually produced the greatest fresh pod yield and highest seed sucrose content. These results demonstrated that late planting after early May might have a negative impact on the eating quality of vegetable soybean.
Rui Zhang, Fang-Ren Peng, Dong-Liang Le, Zhuang-Zhuang Liu, Hai-Yang He, You-Wang Liang, Peng-Peng Tan, Ming-Zhuo Hao and Yong-Rong Li
Scion wood of ‘Caddo’ and ‘Desirable’ pecan (Carya illinoinensis) was grafted onto the epicotyl of 1-month-old, open-pollinated ‘Shaoxing’ pecan seedlings for evaluation as a grafting technique to reduce the time to produce grafted trees. The results showed that seedlings grafted with “base scions” had higher survival than those grafted with “terminal scions” for both ‘Caddo’ and ‘Desirable’. Also, grafting with paraffinic tape could achieve greater success rate than that with medical tape. The most ideal time to perform this grafting was late April in Nanjing, China, when pecan seedlings were about 35 days old. This study demonstrated that the technique yielded successful epicotyl grafting of >70%, and it could thus be applied in practice.