{"id":60,"date":"2022-06-16T13:57:20","date_gmt":"2022-06-16T13:57:20","guid":{"rendered":"https:\/\/blogs.iwu.edu\/freeman2022-ksmit\/?p=60"},"modified":"2022-06-20T00:39:01","modified_gmt":"2022-06-20T00:39:01","slug":"lets-talk-science","status":"publish","type":"post","link":"https:\/\/blogs.iwu.edu\/freeman2022-ksmit\/2022\/06\/16\/lets-talk-science\/","title":{"rendered":"Let’s Talk Science!"},"content":{"rendered":"\n

An introduction to blast fungus (Magnaporthe oryzae<\/em>) in rice<\/strong><\/h4>\n\n\n\n

Today I experienced my first practical application of the science I usually only see happening in the lab or on paper. My supervisor, Dr. Swamy, introduced me to one of his current PhD students, soon-to-be Dr. Tapas Hore, who has been working on an extremely interesting project as part of his thesis. Dr. Hore has been developing a new strain of rice that is more resistant to a notoriously destructive rice disease called Blast.<\/p>\n\n\n\n

Blast (Magnaporthe oryzae)<\/em>, also known as rice seedling blight, Johnson spot, or Imochi, is a fungal disease that can affect rice at any stage of growth. It is caused by the presence and spread of blast spores in areas that have low-moisture, high levels of rainfall, and overall cooler daytime temperatures.<\/p>\n\n\n\n

The presence of blast in rice plants can be detected through physical symptoms such as white to gray-green lesions or spots, with dark green borders or diamond\/spindle-shaped lesions with whitish-gray centers and red-brownish or necrotic borders on the leaf or collar of the rice plant (Figure 1 and Figure 2). These lesions can expand to kill off entire leaves of the rice plant.<\/p>\n\n\n\n

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Figure 1: Spindle-shaped lesions with white centers and red-brown borders<\/figcaption><\/figure><\/div>\n\n\n\n
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Figure 2: Diamond-shaped lesions<\/figcaption><\/figure><\/div>\n\n\n\n

Blast is a serious disease that threatens the growth of rice and, if not controlled, may cause massive reductions or even complete wipeouts of grain yields.<\/p>\n\n\n\n

With the use of genetics, one can isolate genes associated with blast resistance in rice and, through varying combinations of the isolated genes, a strain of rice with desirably increased level of resistance to blast may be established \u2014 methodologies such as QTL* mapping and association mapping* may be used to accomplish this.<\/p>\n\n\n\n

During my introduction to Mr. Hore\u2019s blast project, I learnt that he had isolated 3 particular genes \u2014 Pi9, Pi35 and Pita2 \u2014 associated with blast resistance. These 3 genes were integrated into the genome of a rice breed in varying combinations \u2014 some rice seedlings contained all 3 genes, some had varying combinations of 2 out of the 3 genes, and some only contained 1 out the 3 genes.<\/p>\n\n\n\n

In the screening nursery (Figure 3), where the growth and conditions of the genetically modified rice seedlings are observed and recorded, 3 rice breeds with varying susceptibilities to blast were used as controls (Figure 4) and the 3 were planted next to each other at the beginning of each experimental line which consisted of a further 20 experimental seedlings containing varying combinations of the 3 blast resistance associated genes. The experimental crops are covered every night to ensure an optimal environment is created and to control the spread of blast spores. The success of the genetically modified seedlings for blast resistance was judged by their physical condition i.e. the degree of evidence of blast (Figure 5).<\/p>\n\n\n\n