With the aim to learn about ways of ensuring food supply and security, protecting crops and improving global food security, Faculty of Science (FSc) and Centre for Biodiversity Research (CBR) co-organised an Agriculture Technology webinar on 25 August 2020 via Zoom. The webinar was moderated by FSc academic Assoc Prof Dr Wong Hann Ling.

Invited to share their insights and research findings were Tan Sri Dato’ Philip Kuok Professorial Chair in Agricultural Science Emeritus Prof Dr Minoru Murata and Prof Ivan Galis from the Institute of Plant Science and Resources (IPSR) of Okayama University, Japan.

Titled “An Open Quest for Independent Crops”, Prof Galis shared about crop protection from herbivores by implementing eco-friendly approaches and natural diversity. His research also mentioned that modern agricultural crops are highly productive but also very dependent on various inputs, including fertilizers, herbicides and pesticides. Low input crops and plants that can better sustain stress are therefore desirable, especially in cases when possibilities for providing standard plant care become limited.

“In the current Covid-19 crisis, we could see examples when free movement of labour becomes limited, and in many countries, human health is prioritised over any other activities. We hypothesise that inability to provide plant protection may lead to secondary crises, such as food shortage due to uncontrolled pathogen and herbivore damage to crops. Therefore, in this webinar, I will discuss the possibilities of using natural defence mechanisms against insect herbivores that already evolved in resistant crops and their wild relatives for improvement of plant resilience and survival of crops under adverse conditions. This approach may prove useful in every situation, as it may limit the widespread use of agrochemicals and lead to healthier crops and better protection of our living environment,” explained Prof Galis.

He further stated that food shortages are amplified by losses from pathogens and herbivores. According to the Food and Agriculture Organisation of the United Nations, he pointed out that herbivorous insects are said to be responsible for destroying one-fifth of the world’s total crop production annually. In highlighting the use of natural defence mechanisms, his first suggested strategy was the exploration of genetic diversity. This strategy involves cross-breeding of crop varieties; he found that insects effectively choose their best host plants in the field and this choice is based on the appearance and defence level events on variety level. His research suggested that turning host crop to non-host plants could be a successful mimicry approach for farmers. The second suggested strategy was improvement of mechanical properties, which showed that plants develop mechanical barriers against herbivores. The structural and mechanical properties of barriers determine their efficiency. He suggested to modify mechanical structures through genetic engineering or to improve mechanical properties by mineral supply. He also mentioned that herbivores look for opportunities, and that tall plants offer more space than the shorter ones. He suggested to optimise plants to take the opportunities away from herbivores, such as aim for short variants of successful crops.

His third suggested strategy was to expect the unexpected, which he explained that plants are not alone in the environment. He further explained that complex ecological interactions determine the survival of plants in nature. He suggested to look for smart applications and solutions based on third or higher levels of organisms. Finally, he said that plant species show highly diverse defence level events on variety level. He also pointed out that many resistance genes exist in crops and their wild relative. He advised to look for resistance genes and improve crops by breeding or genetic engineering to produce resilient crops.

Prof Murata, on the other hand, discussed the importance of plant biology in improving food production to avoid food crisis, and to deliver knowledge on crop production. “Malnourishment and hunger were already a major issue for hundreds of millions of people, and about 265 million people were affected by food crisis in 2020, even before the spread of Covid-19. Now with the Covid-19 pandemic, food security crisis may increase if proper measures are not taken. The Covid-19 has not shown, so far, a major direct impact on the supply or price of staple foods in places affected by the virus. However, it may lead to crises in food production. To avoid such kind of crises, plant scientists need to continuously maintain the progress of research activities,” explained Prof Murata.

He also explained about haploids inbreeding and mentioned that haploids may be produced by one of several methods. The first method is another culture, which is meant to induce androgenesis. “The in vitro culturing of anthers containing microspores or immature pollen grains on a nutrient medium for the purpose of generating haploid plants,” said Prof Murata.

He added, “The ovary culture is meant to induce gynogenesis; the in vitro culturing of non-fertilised ovules containing eggs on a nutrient medium to generate haploids plants. The embryo rescue comes from wide (distant) crosses (in vitro), which sees chromosome (genome) elimination. For instance, when barley (Hordeum vulgare) and its relative H. bulbosum are crossed, a normal double fertilisation event occurs. However, during seed development, chromosomes of H. bulbosum are eliminated in both the embryo and endosperm, resulting in haploid production.”

He also talked about centromeres, which he explained as a specialised DNA sequence of a chromosome that links a pair of sister chromatids (a dyad). He said that during mitosis, spindle fibres attached to the centromere via the kinetochore.

“The centromeric DNA is normally in a heterochromatin state, which is essential for the recruitment of the cohesion complex. The normal histone H3 is replaced with a centromere-specific variant, CENH3 (CENP-A in humans). The presence of CENH3 is believed to be important for the assembly of the kinetochore on the centromere. The centromere function requires the centromere-specific histone H3 variant (CENH3), which replaces histone H3 in centromeric nucleosomes and recruits many essential kinetochore proteins. Despite considerable variation in size and sequence, CENH3 protein shows significant conservation of structure and function. CENH3 disruption or overexpression shows severe defects in spindle fibre attachment and ultimately leads to embryo lethality,” explained Prof Murata.

On sharing his thoughts for future research plans, he said the alternative splicing (AS1) seems to occur at a relatively high frequency. “If we could control or raise the alternative splicing, we are able to increase the percentage of mis-targeting to the centromeres. Hence, the CENH3 could not go to the centromeres, resulting in mis-loading. This possibly leads to chromosome dysfunction and results in genome or chromosome elimination. Since alternative splicing is known to be influenced by environmental and external factors, such as temperature, we may be able to control the haploids production by changing the temperature,” said Prof Murata.

The webinar ended with an interactive Q&A session.