Main conclusions

A novel image-based screening method for precisely identifying genotypic variations in rapeseed RSA under waterlogging stress was developed. Five key root traits were confirmed as good indicators of waterlogging and might be employed in breeding, particularly when using the MFVW approach.

Abstract

Waterlogging is a vital environmental factor that has detrimental effects on the growth and development of rapeseed (Brassica napus L.). Plant roots suffer from hypoxia under waterlogging, which ultimately confers yield penalty. Therefore, it is crucially important to understand the genetic variation of root system architecture (RSA) in response to waterlogging stress to guide the selection of new tolerant cultivars with favorable roots. This research was conducted to investigate RSA traits using image-based screening techniques to better understand how RSA changes over time during waterlogging at the seedling stage. First, we performed a t-test by comparing the relative root trait value between four tolerant and four sensitive accessions. The most important root characteristics associated with waterlogging tolerance at 12 h are total root length (TRL), total root surface area (TRSA), total root volume (TRV), total number of tips (TNT), and total number of forks (TNF). The root structures of 448 rapeseed accessions with or without waterlogging showed notable genetic diversity, and all traits were generally restrained under waterlogging conditions, except for the total root average diameter. Additionally, according to the evaluation and integration analysis of 448 accessions, we identified that five traits, TRL, TRSA, TRV, TNT, and TNF, were the most reliable traits for screening waterlogging-tolerant accessions. Using analysis of the membership function value (MFVW) and D-value of the five selected traits, 25 extremely waterlogging-tolerant materials were screened out. Waterlogging significantly reduced RSA, inhibiting root growth compared to the control. Additionally, waterlogging increased lipid peroxidation, accompanied by a decrease in the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). This study effectively improves our understanding of the response of RSA to waterlogging. The image-based screening method developed in this study provides a new scientific guidance for quickly examining the basic RSA changes and precisely predicting waterlogging-tolerant rapeseed germplasms, thus expanding the genetic diversity of waterlogging-tolerant rapeseed germplasm available for breeding.

中文翻译：

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全球 448 个油菜籽 (Brassica napus L.) 的根系结构因涝胁迫而发生变化

主要结论

开发了一种新的基于图像的筛选方法，用于精确识别涝渍胁迫下油菜 RSA 的基因型变异。五个关键的根性状被证实是良好的涝渍指标，可用于育种，特别是在使用 MFVW 方法时。

抽象的

涝渍是对油菜生长发育产生不利影响的重要环境因素。植物根系在涝渍条件下会缺氧，最终导致产量下降。因此，了解根系结构（RSA）响应涝胁迫的遗传变异对于指导选择具有良好根系的新耐性品种至关重要。本研究旨在使用基于图像的筛选技术调查 RSA 性状，以更好地了解 RSA 在苗期涝灾期间如何随时间变化。首先，我们通过比较四个耐受性和四个敏感种质之间的相对根性状值进行t检验。与 12 小时耐涝性相关的最重要的根系特征是总根长 (TRL)、总根表面积 (TRSA)、总根体积 (TRV)、总尖端数 (TNT) 和总分叉数 (TNF) ）。 448份耐涝和未涝的油菜种质的根系结构表现出显着的遗传多样性，除了根系平均直径外，所有性状均在涝渍条件下受到抑制。此外，根据对448份材料的评价和整合分析，我们确定了TRL、TRSA、TRV、TNT和TNF 5个性状是筛选耐涝材料的最可靠的性状。通过对5个性状的隶属函数值(MFVW)和D值进行分析，筛选出25个极度耐涝材料。与对照相比，涝渍显着降低了 RSA，抑制了根系生长。此外，涝渍增加了脂质过氧化作用，并伴随着超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性的降低。这项研究有效地提高了我们对RSA对涝害响应的认识。本研究开发的基于图像的筛选方法为快速检测RSA基本变化和精确预测耐涝油菜种质提供了新的科学指导，从而扩大了可用于育种的耐涝油菜种质的遗传多样性。