Dataset Information

An efficient in vitro regeneration system from different wild apple (Malus sieversii) explants.

ABSTRACT:

Background

Wild apple, Malus sieversii, is an endangered species and a valuable genetic resource that requires a variety of conservation techniques. This study aimed to investigate the influence of different concentrations of hormones on wild apple regeneration from leaf and stem explants to establish an optimal regeneration system.

Results

Leaves and stems derived from seedlings were cultured on several media supplemented with various concentrations of thidiazuron (TDZ) or 6-benzylaminopurine (BA) in different combinations with 1-naphthaleneacetic acid (NAA). The results showed that the most efficient shoot formation media (35% and 90%) were MS medium containing 4.0 mg L^-1 TDZ and 1.0 mg L^-1 NAA for leaf explants and MS medium containing 1.0 mg L^-1 BA without NAA for stem explant. MS medium supplemented with 0.4 mg L^-1 BA and 0.1 mg L^-1 NAA (for shoot multiplication) and 1/2 MS?+?0.1 mg L^-1 NAA?+?1.5% sucrose (for rooting) were effective media. Shoot regeneration from leaf explants was the most effective when the explants were placed abaxial side down onto the medium and were subjected to a pre-treatment of 3 weeks in darkness.

Conclusions

An optimized regeneration system for M. sieversii that allowed regeneration within 2-3 months developed. The protocol developed herein can be used in large-scale clonal propagation for the conservation of wild apple, M. sieversii.

SUBMITTER: Zhang Y

PROVIDER: S-EPMC7175559 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Publications

An efficient in vitro regeneration system from different wild apple (<i>Malus sieversii</i>) explants.

Zhang Y Y Bozorov T A TA Li D X DX Zhou P P Wen X J XJ Ding Y Y Zhang D Y DY

Plant methods 20200421

<h4>Background</h4>Wild apple, <i>Malus sieversii</i>, is an endangered species and a valuable genetic resource that requires a variety of conservation techniques. This study aimed to investigate the influence of different concentrations of hormones on wild apple regeneration from leaf and stem explants to establish an optimal regeneration system.<h4>Results</h4>Leaves and stems derived from seedlings were cultured on several media supplemented with various concentrations of thidiazuron (TDZ) or ...[more]

PMID: 32336979

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Project description:BackgroundWild apple (Malus sieversii) is under second-class national protection in China and one of the lineal ancestors of cultivated apples worldwide. In recent decades, the natural habitation area of wild apple trees has been seriously declining, resulting in a lack of saplings and difficulty in population regeneration. Artificial near-natural breeding is crucial for protecting and restoring wild apple populations, and adding nitrogen (N) and phosphorous (P) is one of the important measures to improve the growth performance of saplings. In this study, field experiments using N (CK, N1, N2, and N3: 0, 10, 20, and 40 g m- 2 yr- 1, respectively), P (CK, P1, P2, and P3: 0, 2, 4, and 8 g m- 2 yr- 1, respectively), N20Px (CK, N2P1, N2P2, and N2P3: N20P2, N20P4 and N20P8 g m- 2 yr- 1, respectively), and NxP4 (CK, N1P2, N2P2, and N3P2: N10P4, N20P4, and N40P4 g m- 2 yr- 1, respectively) treatments (totaling 12 levels, including one CK) were conducted in four consecutive years. The twig traits (including four current-year stem, 10 leaf, and three ratio traits) and comprehensive growth performance of wild apple saplings were analyzed under different nutrient treatments.ResultsN addition had a significantly positive effect on stem length, basal diameter, leaf area, and leaf dry mass, whereas P addition had a significantly positive effect on stem length and basal diameter only. The combination of N and P (NxP4 and N20Px) treatments evidently promoted stem growth at moderate concentrations; however, the N20Px treatment showed a markedly negative effect at low concentrations and a positive effect at moderate and high concentrations. The ratio traits (leaf intensity, leaf area ratio, and leaf to stem mass ratio) decreased with the increase in nutrient concentration under each treatment. In the plant trait network, basal diameter, stem mass, and twig mass were tightly connected to other traits after nutrient treatments, indicating that stem traits play an important role in twig growth. The membership function revealed that the greatest comprehensive growth performance of saplings was achieved after N addition alone, followed by that under the NxP4 treatment (except for N40P4).ConclusionsConsequently, artificial nutrient treatments for four years significantly but differentially altered the growth status of wild apple saplings, and the use of appropriate N fertilizer promoted sapling growth. These results can provide scientific basis for the conservation and management of wild apple populations.

Project description:BackgroundValsa canker is a serious disease in the stem of Malus sieversii, caused by Valsa mali. However, little is known about the global response mechanism in M. sieversii to V. mali infection.ResultsPhytohormone jasmonic acid (JA) and salicylic acid (SA) profiles and transcriptome analysis were used to elaborate on the dynamic response mechanism. We determined that the JA was initially produced to respond to the necrotrophic pathogen V. mali infection at the early response stage, then get synergistically transduced with SA to respond at the late response stage. Furthermore, we adopted Pacific Biosciences (PacBio) full-length sequencing to identify differentially expressed transcripts (DETs) during the canker response stage. We obtained 52,538 full-length transcripts, of which 8139 were DETs. Total 1336 lncRNAs, 23,737 alternative polyadenylation (APA) sites and 3780 putative transcription factors (TFs) were identified. Additionally, functional annotation analysis of DETs indicated that the wild apple response to the infection of V. mali involves plant-pathogen interaction, plant hormone signal transduction, flavonoid biosynthesis, and phenylpropanoid biosynthesis. The co-expression network of the differentially expressed TFs revealed 264 candidate TF transcripts. Among these candidates, the WRKY family was the most abundant. The MsWRKY7 and MsWRKY33 were highly correlated at the early response stage, and MsWRKY6, MsWRKY7, MsWRKY19, MsWRKY33, MsWRKY40, MsWRKY45, MsWRKY51, MsWRKY61, MsWRKY75 were highly correlated at the late stage.ConclusionsThe full-length transcriptomic analysis revealed a series of immune responsive events in M. sieversii in response to V. mali infection. The phytohormone signal pathway regulatory played an important role in the response stage. Additionally, the enriched disease resistance pathways and differentially expressed TFs dynamics collectively contributed to the immune response. This study provides valuable insights into a dynamic response in M. sieversii upon the necrotrophic pathogen V. mali infection, facilitates understanding of response mechanisms to canker disease for apple, and provides supports in the identification of potential resistance genes in M. sieversii.