Rht13 Can Improves Root Structure and Drought Resistance in Wheat

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Wheat is one of the most important crops in the world, feeding about 30% of the global population. However, as the world’s population grows, farmers need to produce more wheat to meet future demands.

One of the biggest challenges they face is drought, which can severely reduce wheat yields. To address this, scientists are studying how certain genes can make wheat more resistant to stress.

A recent study has found that a gene called Rht13 plays a key role in improving wheat’s root growth and its ability to handle drought.

The Importance of Strong Roots in Wheat

Roots are essential for a plant’s survival. They absorb water and nutrients from the soil, anchor the plant, and support its growth. In wheat, the root system consists of two types of roots: seminal roots (the first roots that emerge from the seed) and nodal roots (which develop later).

Seminal roots are especially important because they grow deeper into the soil, allowing the plant to access water and nutrients from lower layers, particularly during dry periods. This makes wheat with stronger and deeper roots more resilient to drought.

The study focused on how the Rht13 gene affects root growth and stress tolerance in wheat. Researchers evaluated 200 different wheat genotypes under both normal and stressful conditions.

They used a chemical called PEG-6000 to simulate drought stress and observed how the plants responded. The goal was to understand how the Rht13 gene influences root architecture and whether it can help wheat plants survive in harsh conditions.

What the Study Found

The researchers discovered that wheat genotypes with the Rht13 gene performed significantly better under stress compared to those without it. Out of the 200 genotypes tested, 21 were found to carry the Rht13 gene.

These genotypes produced five seminal roots, while others without the gene produced only three. For example, genotypes like G-3, G-6, and G-8 had longer roots (over 11 cm), shoots (over 17 cm), and coleoptiles (over 40 cm) under both normal and stressful conditions.

In contrast, genotypes like Ujala-16 and Galaxy-13, which lacked the Rht13 gene, had shorter roots and struggled under stress.

Under osmotic stress, the Rht13 genotypes maintained better growth. For instance, G-3 had a root length of 8.9 cm and a shoot length of 24.22 cm, while Galaxy-13 (without the Rht13 gene) had a root length of only 9.3 cm and a shoot length of 10.2 cm.

This shows that the Rht13 gene helps wheat plants grow stronger roots and shoots, making them more resistant to drought. The study also used statistical analysis to confirm these findings.

The researchers performed a biplot analysis, which showed that seminal roots had a positive correlation with coleoptile length but a negative correlation with shoot length and root length under both normal and osmotic stress conditions.

This means that genotypes with more seminal roots tend to have longer coleoptiles but shorter shoots and roots. These findings highlight the importance of the Rht13 gene in improving root architecture and stress tolerance.

How Rht13 Compares to Other Genes

The study also compared the Rht13 gene to other Rht genes, such as Rht1, which is not sensitive to gibberellic acid (a plant hormone that regulates growth).

The results showed that wheat with the Rht13 gene had better root growth and stress tolerance than wheat with the Rht1 gene.

For example, Rht13 genotypes produced more seminal roots and longer roots, allowing them to access water and nutrients from deeper soil layers. In contrast, Rht1 genotypes had fewer roots and struggled under stress.

The researchers used PCR (Polymerase Chain Reaction) to identify which wheat types carried the Rht13 gene. They found that the gene has a unique structure with 10 conserved motifs, which are involved in functions like drought responsiveness and hormone regulation. This makes the Rht13 gene particularly effective in improving root growth and stress tolerance.

Why This Matters for Farmers

For farmers, especially in areas with limited water, having wheat that can grow strong roots and survive drought is a game-changer. Wheat with the Rht13 gene can access water from deeper soil layers, making it more resilient during dry spells. This not only helps the plant survive but also supports better growth and higher grain yields.

For example, the study found that Rht13 genotypes increased grain yield by up to 50%, which is a significant boost for farmers.

Additionally, wheat with stronger roots can absorb nutrients more efficiently, reducing the need for chemical fertilizers. This is not only cost-effective for farmers but also better for the environment.

By using the Rht13 gene in breeding programs, scientists can develop new wheat varieties that are more productive and resilient, ensuring a stable food supply for the growing population.

The Science Behind Rht13

To understand how the Rht13 gene works, the researchers conducted a phylogenetic analysis, which looks at the evolutionary history of genes.

They found that the Rht13 gene is closely related to other GA-sensitive genes like Rht8 and Rht12, which also improve root growth and stress tolerance.

The motif analysis revealed that Rht13 contains 10 conserved motifs, which are involved in various functions, including drought responsiveness and hormone regulation. These motifs help the gene regulate root growth and improve the plant’s ability to handle stress.

The study also looked at the structure of the Rht13 gene and found that it has no introns (non-coding regions of DNA), which makes it more efficient in regulating root growth. This is different from other Rht genes, like Rht1, which have introns and are less effective in improving stress tolerance.

The Future of Wheat Breeding

The findings of this study have important implications for wheat breeding programs. By incorporating the Rht13 gene into new wheat varieties, breeders can create crops that are more resistant to drought and other stresses. This is especially important as climate change makes weather patterns more unpredictable.

For example, in regions prone to drought, farmers can grow wheat varieties with the Rht13 gene to ensure better yields even in dry conditions.

This not only helps farmers but also contributes to global food security. The study also opens the door for further research into other genes that can improve wheat’s resilience and productivity.

Conclusion

The Rht13 gene is a powerful tool for improving wheat’s ability to handle stress and grow stronger roots. This study shows that wheat with this gene can produce more roots, grow deeper, and survive drought better than wheat without it.

For farmers and scientists, this is a big step forward in the fight against climate change and food insecurity. By using the Rht13 gene in breeding programs, we can create wheat varieties that are not only more resilient but also more productive. This means more food for the world and a brighter future for agriculture. With genes like Rht13, the future of wheat farming looks promising.

Reference: Khalid, M.A., Ali, Z., Husnain, L.A. et al. GA-sensitive Rht13 gene improves root architecture and osmotic stress tolerance in bread wheat. BMC Genom Data 25, 90 (2024). https://doi.org/10.1186/s12863-024-01272-4