雅思阅读 043 · Perennial Rice: Genetic Tinkering Makes It Like Apples

改编自 Science（Erik Stokstad, 2026）。题型：段落信息匹配 + T/F/NG + 填空。难度：中等偏上（Passage 2，约 800 词）。

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🎧 课文朗读音频（约 1 分钟）

正文 Passage

A. The dream of perennial grains

Imagine a grain that comes up every year, with no need to till fields and replant each crop. Farmers would save labour; soil erosion would slow. But developing perennial grains, which would make fields more like long-lasting orchards, has proved laborious.

In 2018, researchers in China introduced a rice variety that can be harvested several years in a row, but creating this strain took decades of traditional breeding.

B. A genetic breakthrough

Genes stolen from a wild species could speed up this process for new varieties of perennial rice tailored for different regions and growing conditions, and now researchers have shown this is possible.

Today in Science, a team identifies two genes that help the wild rice Oryza rufipogon flourish year after year. They added these genes to the cultivated rice O. sativa, which gave it a key perennial trait: the ability to stop flowering and resume vegetative growth, instead of dying off after flowering as annual plants generally do.

"This is a really great advance," says plant biologist Allison Miller of Saint Louis University, who was not involved in the work. "They've identified a really important part of the puzzle."

But, she adds, "This is not the only piece." For one thing, the new growth cannot produce grain.

C. Why annuals won out

Turning rice and other cereals into perennials means overcoming millennia of selective breeding. Annual plants can grow quickly aboveground and produce more grain than wild perennial plants, which often devote considerable resources to developing deeper roots.

During domestication, ancient people selected plants with annual-like traits in part because of their greater grain production.

D. The research

In the new study, plant geneticist Bin Han and developmental biologist Jia-Wei Wang of the Chinese Academy of Sciences teamed up to look for genes that regulate perenniality in rice.

First, they crossed a commonly studied strain of O. rufipogon with a research variety of cultivated rice to create many offspring, each with a different small segment of DNA from the wild species. Looking over the grown plants, they selected one, dubbed G43, that had the essential ability to stop flowering and resume vegetative growth.

All rice plants, even cultivated annual varieties, have a brief second life. After the grain from annual rice is harvested, the plants send up a small second batch of branching stems, called tillers, that also develop grain. But the G43 rice was remarkably prolific, growing about 70 of these secondary tillers, compared with about a dozen put out by their annual rice parent.

E. The genes

The researchers mapped the genes responsible for the late growth to a region on chromosome 1 that they called "endless branches and tillers" (EBT1). Looking deeper, they identified the two specific genes that are responsible: MIR156B and MIR156C.

Both produce microRNAs that bind to specific messenger RNAs, repressing gene activity in a family of other genes that control timing of development from young plants into maturity.

Similar MIR156 genes exist in many grass species, including wheat, and their expression normally drops after a plant has flowered, putting an end to growth. But in G43 these genes behaved differently. Their expression also dropped after flowering, then rose again to allow further vegetative growth of the tillers.

F. Remaining challenges

G43 still grows like an annual plant, upright rather than sprawling along the ground. To change the plants' architecture, the team added two genes to G43 from O. rufipogon, PROG1 and TIG1. The resulting plants exhibited prostrate growth like that of their wild relative, and they lived to the end of a 2-year field trial.

But a bigger hurdle remains for G43. The secondary tillers grew vigorously into new plants, but these plants produced sterile flowers that yielded no grain.

Nevertheless, Moto Ashikari, a plant geneticist at Nagoya University, is impressed with the progress. "This provides a compelling proof of concept that annual crops might be converted into perennial crops through genetic approaches."

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题目 Questions

Questions 1-5: Which paragraph mentions the following?

1. the rice variety introduced in China in 2018

2. ancient people selecting annual-like traits

3. G43 growing about 70 secondary tillers

4. MIR156B and MIR156C producing microRNAs

5. secondary tillers producing sterile flowers

Questions 6-9: T/F/NG

6. Perennial rice fields are like long-lasting orchards.

7. The new G43 rice can produce grain from secondary tillers.

8. MIR156 genes exist only in rice.

9. The research was done at the Chinese Academy of Sciences.

Questions 10-13: Complete the notes. Choose NO MORE THAN TWO WORDS.

• The wild rice species is called (10) ____________.
• The small second batch of branching stems after harvest is called (11) ____________.
• The gene region is called "endless branches and tillers" or (12) ____________.
• The two genes that change growth architecture are PROG1 and (13) ____________.

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答案 Answers

题号	答案
1	A
2	C
3	D
4	E
5	F
6	TRUE
7	FALSE (sterile flowers, no grain)
8	FALSE (exist in many grass species including wheat)
9	TRUE
10	Oryza rufipogon
11	tillers
12	EBT1
13	TIG1

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核心词汇

perennial rice / Oryza rufipogon / O. sativa / gene / microRNA / tillers / chromosome / vegetative growth / domestication / grain / genetic engineering / breeding