植物科学

Histological stains are useful tools for characterizing cell shape, arrangement and the material they are made from. Stains can be used individually or simultaneously to mark different cell structures or polymers within the same cells, and to visualize them in different colors. Histological stains can be combined with genetically-encoded fluorescent proteins, which are useful for understanding of plant development. To visualize suberin lamellae by fluorescent microscopy, we improved a histological staining procedure with the dyes Fluorol Yellow 088 and aniline blue. In the complex plant organs such as roots, suberin lamellae are deposited deep within the root on the endodermal cell wall. Our procedure yields reliable and detailed images that can be used to determine the suberin pattern in root cells. The main advantage of this protocol is its efficiency, the detailed visualization of suberin localization it generates in the root, and the possibility of returning to the confocal images to analyze and re-evaluate data if necessary.

Cannabis seed germination is an important process for growers and researchers alike. Many biotechnological applications require a reliable sterile method for seed germination. This protocol outlines a seed germination procedure for Cannabis sativa using a hydrogen peroxide (H₂O₂) solution as liquid germination media. In this protocol, all three steps including seed sterilization, germination, and seedlings development were carried out in an H₂O₂ solution of different concentrations; 1% H₂O₂ solution showed the fastest and the most efficient germination. This protocol also exhibited high germination efficiency for very old cannabis seeds with lower viability. Overall, this protocol demonstrates superior germination compared to water control and reduces the risk of contamination, making it suitable for tissue culture and other sensitive applications.

Strawberry, including the woodland strawberry Fragaria vesca (2x) and the cultivated strawberry (Fragaria × ananassa, 8x), has emerged as a model system for studying fruit development and ripening. Transient expression provides a quick assay for gene functions or gene interactions. In strawberry, virus-induced gene silencing (VIGS) and Agrobacterium tumefaciens-mediated transformation in fruit have been widely used as the transient expression approaches. Unlike VIGS, the latter one can be utilized not only for gene knock-down, but also for overexpression and knock-out. Here, we show the procedures of transiently expressing the 35S::FveMYB10 construct into fruit of the white-fruited F. vesca accession Yellow Wonder. As a master regulator of anthocyanin production, overexpressing FveMYB10 will cause fruit coloration, which was observed at one week post infiltration. We also exhibit the previous results of knocking down Reduced Anthocyanin in Petioles (RAP), encoding an anthocyanin transporter, by RNAi in fruit of the strawberry cultivar ‘Sweet Charlie’. Overall, Agrobacterium-mediated transient transformation in strawberry fruit is a quick and versatile approach for studying gene functions in fruit ripening.

Plant vascular systems in the stem connect roots with aerial organs to move solutes containing minerals, nutrients as well as signaling molecules, and therefore, they play pivotal roles in plant growth and development. However, stem vascular systems, especially in crop species, have been poorly described since they are deeply embedded in the tissue. Here we describe a protocol to utilize micro-computed tomography (micro-CT) scanning to visualize vascular networks in the maize stem. The protocol covers sample fixation and staining with contrasting reagents, data acquisition using micro-CT, reconstructing three-dimensional (3D) models of stem inner structures and extraction of vascular networks from the model. This protocol can be easily applied to various types of species and organs/tissues.

The shoot apical meristem is the origin of bamboo wood. Its structure and morphology are important for maintaining the normal development of bamboo wood. However, the traditional method to describe the morphology of the shoot apical meristem in bamboo or other plants only depends on qualitative approaches. Here we present a protocol for precisely describing the morphology of bamboo shoot apical meristem, which is adapted from our recently published papers (Shi et al., 2015; Wei et al., 2017).

Phenotyping the dynamics of root responses to environmental cues is necessary to understand plant acclimation to their environment. Continuous monitoring of root growth is challenging because roots normally grow belowground and are very sensitive to their growth environment. This protocol combines infrared imaging with hydroponic cultivation for kinematic analyses. It allows continuous imaging at fine spatiotemporal resolution and disturbs roots minimally. Examples are provided of how the procedure and materials can be adapted for 3D monitoring and of how environmental stress may be manipulated for experimental purposes.

Since the discovery of the CRISPR (clustered regularly interspaced short palindromic repeats)-associated protein (Cas) as an efficient tool for genome editing in plants (Li et al., 2013; Shan et al., 2013; Nekrasov et al., 2013), a large variety of applications, such as gene knock-out, knock-in or transcriptional regulation, has been published. So far, the generation of multiple mutants in plants involved tedious crossing or mutagenesis followed by time-consuming screening of huge populations and the use of the Cas9-system appeared a promising method to overcome these issues. We designed a binary vector that combines both the coding sequence of the codon optimized Streptococcus pyogenes Cas9 nuclease under the control of the Arabidopsis thaliana UBIQUITIN10 (UBQ10)-promoter and guide RNA (gRNA) expression cassettes driven by the A. thaliana U6-promoter for efficient multiplex editing in Arabidopsis (Yan et al., 2016). Here, we describe a step-by-step protocol to cost-efficiently generate the binary vector containing multiple gRNAs and the Cas9 nuclease based on classic cloning procedure.

Electro-fusion system with isolated gametes has been utilized to dissect fertilization-induced events in angiosperms, such as egg activation, zygote development and early embryogenesis, since the female gametophytes of plants are deeply embedded within ovaries. In this protocol, procedures for isolation of rice gametes, electro-fusion of gametes, and culture of the produced zygotes are described.

Dissecting the gene regulatory networks (GRNs) underlying developmental processes is a central goal in biology. The characterization of the GRNs underlying flower development has received considerable attention, however, novel approaches are required to reveal temporal and spatial aspects of these GRNs. Here, we provide an overview of the options available to perform dynamic gene perturbations to identify downstream response genes at specific stages of development in the flowers of Arabidopsis thaliana.

Microtubules (MTs) support an astonishing set of versatile cellular functions ranging from cell division, vesicle transport, and cell and tissue morphogenesis in various organisms. This versatility is in large mediated by MT-associated proteins (MAPs). The neuronal MAP Tau, for example, is stabilizing MTs in axons of the vertebrate nervous system and thus provides the basis for enduring axonal transport and the long life span of neurons (Mandelkow et al., 1994). Tau has been shown to bind to MTs directly in vitro and also to promote their nucleation from α-/β-tubulin subunits (Goode et al., 1994). Recently, we identified a plant-specific protein family called “companion of cellulose synthase” (CC), which was shown to bind MTs and enhance dynamics of the cortical MT array in plant cells under salt stress (Endler et al., 2015). The CCs were therefore hypothesized to help plant cells cope with stress conditions and thereby maintain biomass production under adverse growth conditions. Here, we provide detailed experimental information on in vitro MT binding assays, which allow assessing whether a protein of interest is binding to MTs. The assay utilizes the high molecular weight of MTs in a spin down approach and enables the determination of the dissociation constant K_d, a measure for the protein’s binding strength to MTs.