Milk thistle (Silybum marianum (L.) Gaertn.), a valuable medicinal plant with economic importance, serves as a source of both therapeutic compounds and vegetable oil for human use. Genome editing techniques have been widely applied to improve key agronomic traits in various species. Therefore, this study aims to develop an efficient method for seed sterilization and protoplast isolation in milk thistle. For seed sterilization, seed treated with hydrogen peroxide for either 4 hours or 7 hours with ethanol and detergent showed more sufficient to sterilize seed of milk thistle for in vitro growth than ethanol, sodium hypochlorite, and chlorine gas. For protoplast isolation in milk thistle, high-yielding, viable protoplasts were successfully isolated from the leaves of 21-day-old plants using a 2 hours enzymatic treatment containing 2% Viscozyme^® L, 1% Celluclast^® 1.5 L, and 1% Pectinex^® Ultra SP-L. Additionally, transient expression of green fluorescent protein was observed following polyethylene glycol-mediated transfection. Therefore, the seed sterilization and protoplast isolation methods developed in this study can facilitate in vitro culture, gene function analysis, and genome editing aimed at improving agronomic traits in milk thistle.

Adzuki bean (Vigna angularis [Willd.] Ohwi & Ohashi) has recently become widely cultivated in Asia. Generally, it is sensitive to flooding stress. Wild relatives of adzuki bean have shown higher tolerances to abiotic stressors than cultivars, but their responses to flooding are not well understood. In this study, the waterlogging tolerance levels of 202 accessions from two cultivated Vigna species including V. angularis var. angularis (cultivated adzuki bean), V. umbellata (rice bean), and two wild ones consisting of V. angularis var. nipponensis (wild adzuki bean), and V. nakashimae, were evaluated at the early vegetative stage using a foliar damage score. Additionally, the responses of 119 accessions from V. angularis var. nipponesis bean and V. nakashimae to submergence at the germination stage were evaluated using germination-related traits. Among the tested species, cultivated adzuki bean showed the lowest tolerance to waterlogging, while V. nakashimae showed the greatest. At the germination stage, seeds of V. nakashimae were more tolerant of submergence than seeds of V. angularis var. nipponesis, exhibiting significantly higher normal seedling indexes. There was no significant correlation between the early vegetative-stage index and either germination-stage index for both V. angularis var. nipponensis and V. nakashimae, suggesting that the genetic bases regulating flooding stress responses at the two growth stages differ. However, we identified four V. nakashimae accessions that exhibited tolerant or very tolerant responses to flooding at both stages, suggesting their potential for use in breeding flood-tolerant adzuki bean varieties.

Doubled haploid (DH) technology enables the generation and evaluation of new plant genotypes in ≤ 2 years, which is in stark contrast to the 6-7 years required for conventional breeding. Recently, a few proteins including MATRILINEAL (MTL) were found to trigger haploid induction in monocot plants. However, MTL function in dicot plants remains unclear. Here, we investigate the effects of Arabidopsis PATATIN-RELATED PHOSPHOLIPASE 2A (pPLA-IIa), a maize MTL homolog, on the expression of genes that modulate pollen development and fertilization in Arabidopsis. Quantitative real-time PCR analysis showed that transcript levels of four pollen tube growth-related genes and six pollen guidance- or reception-related genes were increased in the ppla-iia T-DNA insertion mutant compared with the wild type. In addition, transcript levels of four mitosis- and meiosis-related genes, two hormone-related genes, and a calcium pump-encoding gene were also upregulated in the ppla-iia mutant, whereas expression levels of genes encoding a synergid-secreted peptide (AtLURE1.1) and calmodulin-activated Ca^2＋-ATPase ion pump 9 (ACA9) protein were downregulated in the ppla-iia mutant compared with the wild type. Taken together, these results suggest that AtLURE1.1 and ACA9 play positive roles in pPLA-IIa-mediated fertilization. Thus, pPLA-IIa controls fertilization through the modulation of pollen germination and pollen tube growth and guidance in Arabidopsis.

Pathogen attack and abiotic stress affect grain yields in rice fields worldwide. Rice leaf blast is caused by the fungal pathogen Magnaporthe oryzae, whereas rice leaf blight is caused by the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo). Rice leaf blast and blight, the two most destructive diseases in rice, result in huge yield losses. We therefore tried to identify a chemical that could be utilized as an inhibitor of rice leaf blast and blight. Here, we show that both bacterial-induced rice blight and fungal-induced rice blast can be controlled by auranofin, an anti-rheumatoid arthritis and anti-cancer drug used in humans. Auranofin directly inhibited the growth of four Xoo strains, including PXO99, KACC10208, 1209, and 1308. In addition, auranofin effectively controlled the growth of 10 M. oryzae strains, including KACC46531, 46532, 46534, 46535, 46536, 46538, 46540, 46541, 46542, and 46544, although its effect on M. oryzae was weaker than that on Xoo. These results suggest that auranofin can be applied to rice to block both rice leaf blight and blast caused by Xoo and M. oryzae, respectively.

There is a growing preference for using doubled haploids (DHs) in maize breeding programs because they reduce the time required to generate and evaluate new lines to 2 years or less. However, there is an urgent need for efficient techniques that accurately discriminate between haploid and diploid maize kernels. Here, we investigate the effects of several hormones and chemicals on the germination of haploid and diploid maize kernels, including auxin, cytokinin, ethylene, abscisic acid (ABA) biosynthesis inhibitor (fluridone), ABA catabolism inhibitor (diniconazole), methyl jasmonate (MeJA), and NaCl. Ethylene effectively stimulated the germination of both haploid and diploid maize kernels. The ABA biosynthesis inhibitor fluridone, the ABA catabolism inhibitor diniconazole, and MeJA selectively stimulated the germination of haploid maize kernels. By contrast, gibberellin, 1-naphthaleneacetic acid (NAA), kinetin, and NaCl inhibited the germination of both haploid and diploid maize kernels. These results indicate that the germination of haploid maize kernels is selectively stimulated by fluridone and diniconazole, and suggest that ABA-mediated germination of haploid maize kernels differs from that of diploid maize kernels and other plant seeds.

Citations

Citations to this article as recorded by  

• Maize Doubled Haploid Technology: A New Breeding Paradigm
  Van Gioi Ha, Hwi Moon, Yoon-Sup So
  Korean Journal of Breeding Science.2024; 56(4): 471.     CrossRef

Ascorbate peroxidases (APXs) are enzymes that detoxify peroxides such as hydrogen peroxide using ascorbate. They are distributed as isoenzymes in distinct cellular compartments, such as the cytosol, mitochondria and peroxisomes, where they play essential roles in scavenging reactive oxygen species (ROS) and protecting cells against the toxic effects of these species in higher plants, algae, euglena and other organisms. APXs also respond to environmental stresses, such as salinity and drought, and rice ascorbate peroxidase 1 (OsAPx1) participates in salinity tolerance. However, it is still unclear how OsAPx1 is involved in growth and development before and after flowering. Here, we show that OsAPx1 plays an important function in seed development, including fertilization. Proteomic analysis and quantitative RT-PCR showed that protein and mRNA levels of OsAPx1 were much higher in immature seeds than in mature seeds. Plant height and grain size in an Osapx1 mutant were almost the same as those in wild-type plants. However, about 58% of the seeds were aborted in the Osapx1 mutant, although the mutant was capable of normal flowering. Our results suggest that rice ascorbate peroxidase functions both as a regulator of seed development and as a scavenger of ROS.

Citations

Citations to this article as recorded by  

• Prediction of new candidate proteins and analysis of sub-modules and protein hubs associated with seed development in rice (Oryza sativa) using an ensemble network-based systems biology approach
  M. R. P. De Silva, J. W. J. K. Weeraman, S. Piyatissa, P. C. Fernando
  BMC Plant Biology.2025;[Epub]     CrossRef
• Expression profiling of flowering time pathway in the L-ascorbate peroxidase 9 (APX9) near-isogenic line derived from an interspecific cross between Korean Japonica rice (Oryza sativa L.) and Oryza rufipogon
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  Genes & Genomics.2025; 47(11): 1163.     CrossRef
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  Bixin Bai, Guoding Zhang, Baoyan Pei, Qingting Song, Xing’an Hao, Lei Zhao, Yunfeng Wu
  Journal of Biological Chemistry.2023; 299(4): 103052.     CrossRef
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  Yun-A Jeon, Hyun-Sook Lee, Sun-Ha Kim, Kyu-Chan Shim, Ju-Won Kang, Hyun-Jung Kim, Thomas H Tai, Sang-Nag Ahn, Christine Foyer
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  Shivi Tyagi, Shumayla, Praveen Chandra Verma, Kashmir Singh, Santosh Kumar Upadhyay
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  Deepti Somayajula, Neetin Desai
  Heliyon.2019; 5(12): e02968.     CrossRef
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