Biology subjects

Chang, H.-X.

Publications and source records attributed to Chang, H.-X..

3 recordsLinked to original sources

bioRxiv2024

Rhizobium rhizogenes A4-derived strains mediate hyper-efficient transient gene expression in Nicotiana benthamiana and other solanaceous plants

Agroinfiltration, a method utilizing agrobacteria to transfer DNA into plant cells, is widely used for transient gene expression in plants. Besides the commonly used Agrobacterium strains, Rhizobium rhizogenes can also introduce foreign DNA into host plants for gene expression. While many R. rhizogenes strains have been known for inducing hairy root symptoms, their use for transient expression has not been fully explored. Here, we showed that R. rhizogenes A4 outperformed all other tested agrobacterial strains in agroinfiltration experiments on leaves of Nicotiana benthamiana and other solanaceous plants. By conducting an agroinfiltration screening in N. benthamiana leaves using various agrobacterial strains carrying the RUBY reporter gene cassette, we discovered that A4 mediates the strongest and fastest transient expression. Utilizing the genomic information, we developed a collection of disarmed and modified strains derived from A4. By performing vacuum infiltration assays, we demonstrated that these A4-derived strains efficiently transiently transform 6-week-old N. benthamiana leaves, showing less sensitivity to the age of plants compared to the laboratory strain GV3101. Furthermore, we performed agroinfiltration using AS109, an A4-derived disarmed strain, on the leaves of tomato, pepper, and eggplant. Remarkably, AS109 mediated transient gene expression on tested solanaceous plants more effectively than all the tested commonly used agrobacterial strains. This discovery paves the way for establishing R. rhizogenes A4-derived strains as a new option for enhancing transient expression in N. benthamiana and facilitating the functional study of plant genes in other solanaceous species.

plant biology↗

bioRxiv2023

Colonization of Bacillus altitudinis on the Compatible Soybean Varieties to Provide Seed Rot Resistance

Seed health is crucial for plant growth and agricultural productivity. Recent studies have illustrated the importance of plant microbiome in disease resistance, however, it remains unclear whether the seed microbiome confers seed rot resistance against fungal pathogens. In this study, the application of antibiotics on the seeds of eight soybean varieties showed that seed-associated bacteria were involved in the seed rot resistance caused by Calonectria ilicicola, but this resistance cannot be carried to withstand root rot. Using PacBio 16S rDNA full-length sequencing and microbiome analyses, the seed microbiome was shown to mainly dependent on the soybean variety, and there was no consistent community network associated with seed rot resistance across soybean varieties. Instead, the seed-associated Bacillus altitudinis was identified through the differential abundance analysis and culture-dependent isolation. Moreover, qPCR confirmed the persistence of B. altitudinis on apical shoots till 21 days post-inoculation, but not on roots by 9 days post-inoculation. The short-term colonization of B. altitudinis on roots may explain the absence of root rot resistance. Furthermore, seed treated with B. altitudinis restored seed rot resistance, but only in the compatible soybean varieties. For the incompatible soybean varieties, B. altitudinis showed lower bacterial density and provided no seed protection. Collectively, this study advances the insight of B. altitudinis conferring seed rot resistance. These findings highlight the potential of using seed-associated bacteria for seed protection and underscore the importance of considering bacterial compatibility with plant genotypes and tissues.

plant biology↗

bioRxiv2017

Exploring the Genetics of Lesion and Nodal Resistance in Pea (Pisum sativum L.) to Sclerotinia sclerotiorum Using Genome-wide Association Studies and RNA-Seq

The disease white mold caused by the fungus Sclerotinia sclerotiorum is a significant threat to pea production and improved resistance to this disease is needed. Nodal resistance in plants is a phenomenon where a fungal infection is prevented from passing through a node and the infection is limited to an internode region. Nodal resistance has been observed in some pathosystems such as the pea (Pisum sativum L.)-S. sclerotiorum pathosystem. Other than nodal resistance, different pea lines display different levels of stem lesion size restriction, referred to as lesion resistance. It is unclear whether the genetics of lesion resistance and nodal resistance are identical or different. This study applied genome-wide association studies (GWAS) and RNA-Seq to understand the genetic makeup of these two types of resistance. The time series RNA-Seq experiment consisted of two pea lines (the susceptible Lifter and the partially resistant PI 240515), two treatments (mock samples and S. sclerotiorum inoculated samples), and three time points (12, 24, and 48 hours post-inoculation). Integrated results from GWAS and RNA-Seq analyses identified different redox-related transcripts for lesion and nodal resistances. A transcript encoding a glutathione S-transferase was the only shared resistance source for both phenotypes. There were more leucine rich-repeat containing transcripts found for lesion resistance, while different candidate resistance transcripts such as a VQ motif-containing protein and a myo-inositol oxygenase were found for nodal resistance. This study demonstrated the robustness of combining GWAS and RNA-Seq for identifying white mold resistance in pea, and results suggest different genetics underlying lesion and nodal resistance.

plant biology↗