Plant Root
Online ISSN : 1881-6754
ISSN-L : 1881-6754
Volume 14
Displaying 1-4 of 4 articles from this issue
Published on January 14, 2021
  • Siti Noorrohmah, Hirokazu Takahashi, Mikio Nakazono
    2020 Volume 14 Pages 33-41
    Published: 2020
    Released on J-STAGE: January 14, 2021
    JOURNAL FREE ACCESS

    A barrier to restrict radial oxygen loss (ROL) promotes the adaptation of plants to waterlogged soil conditions. A ROL barrier is formed in the basal parts of roots and contributes to the enhancement of the longitudinal diffusion of oxygen (O2) via aerenchyma toward the root tips. The adventitious roots of rice (Oryza sativa) can form a ROL barrier in waterlogged soil; however, whether a ROL barrier can be formed in the lateral roots (LRs) of rice remains unclear. Rice possesses two types of LRs: L- and S-type. L-type LRs are generally long, thick, and capable of branching, whereas S-type LRs are short, thin, and incapable of branching. In this study, we examined whether the L- and S-type LRs of rice possess the ability to form ROL barriers. In L-type LRs, a ROL barrier was formed; the aerenchyma, which is constitutively formed under aerated conditions, was further developed under stagnant deoxygenated conditions, suggesting that these traits promote the supply of O2 to the root tips of LRs. However, neither a ROL barrier, nor aerenchyma was formed in S-type LRs, and thus ROL was observed mostly in the basal parts. Patterns of deposition of suberin, which is thought to be one of the components of the ROL barrier, were consistent with the patterns of ROL-barrier formation in L-type and S-type LRs. These results suggest that L- and S-type LRs play distinct roles in the growth of rice plants in waterlogged soils and in oxygenating the rhizosphere.

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Published on November 12, 2020
  • Masahiko Mori, Atsushi Oyanagi, Emdadul Haque, Kentaro Kawaguchi, Hide ...
    2020 Volume 14 Pages 23-31
    Published: 2020
    Released on J-STAGE: November 12, 2020
    JOURNAL FREE ACCESS

    The identification of genetic factors affecting deep root systems is needed to improve adaptability to drought stress. In wheat (Triticum aestivum L.), seminal root angle (SRA), which can be easily measured at the seedling stage, is a useful proxy for understanding the mature root system architecture. In the present study, we attempted to find a genetic variation in the vertical distribution of seminal roots and to determine chromosomal positions involved in a variation of SRA using ditelosomic (Dt) lines and deletion lines of wheat cultivar Chinese Spring (CS). SRA of CS and 31 Dt lines were estimated in a pot experiment using the basket method. When SRA was measured separately for the primary, first pair, and second pair of seminal roots, it was found that the genetic variation was the largest in the first pair of seminal roots followed by the second pair of seminal roots. In contrast, there were no genetic differences in the SRA of the primary root between the CS and CS Dt lines. Compared to CS, which had a small SRA, Dt5BL, Dt6AS, Dt6BS, and Dt6DS displayed significantly larger SRA, indicating that the deficient chromosome arms 5BS, 6AL, 6BL, and 6DL appeared to carry quantitative trait loci (QTLs) affecting SRA. Furthermore, the terminal regions of chromosome arms 6AL and 6BL were found to carry QTLs responsible for a small SRA. Using the QTLs information obtained in this study, novel genes may be isolated from wheat.

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Published on October 9, 2020
  • Emdadul Haque, Eiji Yamamoto, Kenta Shirasawa, Hiroaki Tabuchi, Ung-Ha ...
    2020 Volume 14 Pages 11-21
    Published: 2020
    Released on J-STAGE: October 09, 2020
    JOURNAL FREE ACCESS

    Genetic studies on the purple-fleshed sweetpotato (Ipomoea batatas L.), which is rich in anthocyanin (AN) in the storage root, were performed by polyploid GWAS based on the allele dosage probability using 59,675 SNPs obtained from 94 F1 progenies between the cultivars 'Konaishin' (which has a high yield but no AN) and 'Akemurasaki' (which has a high AN content but low to moderate yield). The distribution of relative AN content was highly biased, with 60% of clones showing a low to undetectable level (A530 < 0.5). Fifty-nine SNPs from six signals on homologous groups (HGs) 3, 5 (one major and one smaller signal), 7, 13, and 15 were strongly associated with the relative AN content. Twelve SNPs from the major signal and one from the smaller signal of HG 5 were further detected by QTL analysis. In a database search of the AN biosynthesis gene, transcription factors IbMYB1 and IbWD40 and AN structural genes IbF3H and IbDFR were located on HG 5, suggesting that an SNP marker or markers from HG 5 might be tightly linked to candidate gene(s) homologous to one of these transcription factors and AN structural genes as a major factor in determining AN accumulation in the storage roots. These results would enhance our understanding of the underlying genetic basis of AN accumulation in the storage roots of sweetpotatoes, and the SNP markers found here, especially 13 SNPs from HG 5, would be a potential platform for future marker-assisted selection for breeding high-AN sweetpotato varieties.

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Published on September 3, 2020
  • Takashi Baba, Dai Hirose
    2020 Volume 14 Pages 1-10
    Published: 2020
    Released on J-STAGE: September 03, 2020
    JOURNAL FREE ACCESS

    Lifecycle and temporal functionality of ericaceous fine roots can be affected by colonization dynamics of diverse root colonizing fungi. However, states of colonization are unknown for most of the root endophytes, which also obscures their lifestyles. To recognize characteristics of colonization of Leohumicola fungi, we investigated (1) the vitality of rhizodermal cells by using FUN-1 stain (vital staining) and (2) morphology of colonizing hyphae by N-acetylglucosamine-specific staining (DAB staining). All the twelve strains, identified as L. verrucosa, L. minima, and Leohumicola spp., colonized vital and non-vital rhizodermal cells of Vaccinium seedlings. We observed at least four different states of host cells encompassing coils. DAB staining visualized intracellular hyphae that resembled coils of typical ericoid mycorrhizal fungi. Heterogeneous staining states of coils were also observed in DAB staining. The variable states of Leohumicola coils can be comparable with ericoid mycorrhizal fungi, and indicate various developmental and functional stages of intracellular association.

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