Featured Research

from universities, journals, and other organizations

Amazing Maze Of Maize Evolution: Study On Maize Domestication May Help Improve Crop Yields

Date:
October 5, 2009
Source:
American Journal of Botany
Summary:
Understanding the evolution and domestication of maize is important for many researchers. As one of the most important crops worldwide and one that appears very different from its wild relatives because of domestication, understanding exactly how maize has evolved has many practical benefits and may help improve crop yields. Researchers recently compared corn kernel development to its closest wild relative and have overturned some commonly held beliefs on the domestication of maize.

This is a longitudinal section of developing caryopsis of maize ancestor, teosinte (Zea mays ssp. parviglumis, caryopsis diameter cca. 3 mm). Teosinte plants differ significantly from domesticated maize Zea mays ssp. mays. Teosinte plants have many lateral branches with terminal male inflorescences, which closely resemble maize tassels, and small female inflorescences or “ears”, which are very different from maize ears, in leaf axils. Kernels in the teosinte ears are arranged in two rows and enclosed in hard cupulate fruitcases (fruitcases turn brown if they contain fertilized kernels), and they disarticulate at maturity. In contrast with the highly dissimilar morphology of the teosinte caryopsis, various cellular processes in the filial seed inside the glumes are remarkably similar to maize (which lacks prominent glumes). Endosperm cells in the developing teosinte kernels undergo endoreduplication—multiple duplications of the whole nuclear genome without intervening cell division, resulting in endopolyploid cells. The colored bubbles superimposed on a section of the developing teosinte kernel represent the nuclei in the seed (embryo and endosperm) and in the pericarp (mature ovary wall). Different classes of endopolyploidy are represented by different colors, and the size of the bubbles is proportional to the ploidy level of the nuclei.
Credit: Aleš Kladnik

Understanding the evolution and domestication of maize has been a holy grail for many researchers. As one of the most important crops worldwide and as a crop that appears very different from its wild relatives as a result of domestication, understanding exactly how maize has evolved has many practical benefits and may help to improve crop yields.

In the October issue of the American Journal of Botany, Dr. Marina Dermastia and colleagues published their research comparing corn kernel development to its closest wild relative: teosinte. This research overturns some commonly held beliefs on the domestication of maize because, unexpectedly, many traits seen in the cellular development of maize kernels that were previously attributed to the process of domestication were observed in the development of the teosinte kernels by Dermastia and her colleagues. "Although the teosinte kernels are morphologically so different from that of maize, their inside is not, Dermastia said. "Although we did not expect fundamental differences between maize and teosinte, the similarities were striking."

Some of the traits thought to be unique to maize but now also found in teosinte include an early programmed cell death for cells in part of the kernel and accumulation of phenolic and flavonoid compounds in the walls of these cells. These developmental changes strengthen the cells, protect them against decay and disease, and increase water conductance. According to Dermastia, "We suggested previously that this process was important for the establishment of the water and assimilate flow to the developing maize kernel…in the teosinte kernel, we not only detected programmed cell death…but also all other phenomena described as related to the transport into the maize kernel." The presence of these traits in teosinte kernels suggests that they are not a consequence of maize domestication.

Other developmental traits they observed in the teosinte kernels included the presence of an enzyme that controls the flow of sugar in the developing seed, which appears to be a common mechanism for sugar uptake in both maize and teosinte.

Dermastia and her colleagues did observe one difference between seed development in teosinte and maize. Endoreduplication, the process of a cell duplicating its DNA without subsequent cell division, is a phenomenon that occurs in the endosperm of cereals, which is the nutritious part of the seed. An increasing rate of endoreduplication results in cells with greater DNA content and, subsequently, increased gene expression and greater sink capacity for the developing seed. Dermastia and her colleagues observed that the distribution of cells with high DNA content in maize differs from that of teosinte. In maize, these cells are found in the upper part of the endosperm, while in teosinte they are distributed throughout the endosperm. The researchers hypothesize that this difference may be related to more efficient starch deposition in maize as a result of domestication.

"Our study indicates that the main differences, beside the teosinte fruitcase and its absence in maize, might lay in the process of endoreduplication in endosperm, Dermastia said. "Knowing the process in more depth might be an important step in improving a most important crop."


Story Source:

The above story is based on materials provided by American Journal of Botany. Note: Materials may be edited for content and length.


Journal Reference:

  1. Dermastia, Marina, Kladnik, Ales, Dolenc Koce, Jasna, Chourey, Prem S. A cellular study of teosinte Zea mays subsp. parviglumis (Poaceae) caryopsis development showing several processes conserved in maize. Am. J. Bot., 2009; 96: 1798-1807 DOI: 10.3732/ajb.0900059

Cite This Page:

American Journal of Botany. "Amazing Maze Of Maize Evolution: Study On Maize Domestication May Help Improve Crop Yields." ScienceDaily. ScienceDaily, 5 October 2009. <www.sciencedaily.com/releases/2009/10/091002182631.htm>.
American Journal of Botany. (2009, October 5). Amazing Maze Of Maize Evolution: Study On Maize Domestication May Help Improve Crop Yields. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2009/10/091002182631.htm
American Journal of Botany. "Amazing Maze Of Maize Evolution: Study On Maize Domestication May Help Improve Crop Yields." ScienceDaily. www.sciencedaily.com/releases/2009/10/091002182631.htm (accessed September 20, 2014).

Share This



More Plants & Animals News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: San Diego Zoo Welcomes Cheetah Cubs

Raw: San Diego Zoo Welcomes Cheetah Cubs

AP (Sep. 20, 2014) The San Diego Zoo has welcomed two Cheetah cubs to its Safari Park. The nearly three-week-old female cubs are being hand fed and are receiving around the clock care. (Sept. 20) Video provided by AP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins