# Analysis of the Genetic Diversity of Houttuynia cordata Thunb Germplasm and Associated Variations in Lead Content

## TL;DR

This study identifies genetic markers in Houttuynia cordata plants that help screen for varieties with low lead absorption, making them safer to eat.

## Contribution

The study introduces two ISSR loci (Locus 21 and Locus 29) as molecular markers for screening low lead-absorbing Houttuynia cordata germplasm.

## Key findings

- Five major classes of Houttuynia cordata were identified based on morphological traits.
- Underground stem thickness was closely related to lead absorption.
- Two ISSR loci (Locus 21 and Locus 29) effectively screen for low lead-absorbing germplasm.

## Abstract

Houttuynia cordata
is an important medicinal and vegetable crop in Southwest China. Due to the accumulation of heavy metal ions such as lead ions (Pb2+) in
H. cordata
, consumption of this plant carries risks, such as ingestion of lead‐contaminated
H. cordata
, may lead to Pb2+ bioaccumulation, which is associated with developmental retardation, endocrine disruption, and impairments to immune and neurological functions. In order to screen
H. cordata
germplasm for low Pb2+ absorption and identify the Pb2+ adsorption‐related agronomic traits and molecular markers, the genetic diversity of a germplasm resource of
H. cordata
comprising collected 72 accessions was comprehensively evaluated based on agronomic traits and Pb2+ contents in the underground stems of the plant. Further, intersimple sequence repeats (ISSR) markers and generalized linear model (GLM) correlation analyses were performed to identify the ISSR loci related to the Pb2+ absorption. Ward clustering analysis grouped the 72 accessions of
H. cordata
into five major classes through analysis of morphological traits. Combined analysis of the Pb2+ contents of underground stems with the phenotypic traits revealed significant changes in members within the five classes, indicating that the Pb2+ content significantly affected the results of the evaluation of agronomic traits. Greyscale analysis and subsequent verification revealed that the underground stem thickness was closely related to the Pb2+ absorption. Based on ISSR markers and subsequent verification, two loci, namely, Locus 21 and Locus 29, were found to have better screening effects on germplasms with low Pb2+ adsorption. The accessions that did not carry these two loci in the genome generally exhibited low lead ion adsorption. This study presents a faster marker‐based screening for
H. cordata
plants that are safer for consumption.