This question appears to be about patent application US20200061138A1. Within US patent law, there are two relevant questions. First, the question of whether the US patent system allows this type of thing to be patented, also called patent-eligible subject matter. Second, whether the claims are directed to something new and not obvious, also called an inventive step.
US20200061138A1 has two main claims. Claim 1 is directed to a method for increasing cannabinoids in a genetically modified Cannabis sativa, performed by over-expressing certain enzymes in the plant. Claim 10 is directed to a chemical compound, most commonly known as CBD or cannabidiol. I will discuss the patentability of the genetically modified plant separately from the chemical compound.
Plants in general, and genetically modified plants in particular, are patent-eligible subject matter. See the USPTO's manual chapter 2105 (https://www.uspto.gov/web/offices/pac/mpep/s2105.html).
Moving on, claim 10 is directed to the chemical 2-((1R,5R)-3-methyl-5-(prop-1-en-2-yl)cyclopent-2-en-1-yl)-5-pentyl benzene-1,3-diol (paragraph 0030). This is also known as cannabidiol, CBD, and under the trade name Epidiolex. Chemical compounds are patent eligible subject matter. Claim 10 is directed to a chemical compound that is well known (cannabidiol, CBD, Epidiolex). Accordingly, it is not new.
Finally, claims 14, 15, 19 and 20 are directed to broad methods of administering mixtures containing CBD for treating broad classes of disease. The USPTO has issued at least one patent (US9474726B2) for using CBD to treat a different disease (epilepsy; this was approved by the FDA under the trade name Epidiolex). These methods to treat disease are also patent-eligible.
As regards whether or not the claimed subject matter is new and not obvious, we can wait to see what the USPTO after review. The Applicant did cite previously known methods for genetically modifying plants (paragraphs 0025, see also paragraphs 0026-0029). Furthermore, the Applicant provided a motivation to increase these enzymes in Cannabis, in order to have higher concentrations of the active cannabinoids (paragraph 0012).
I hope this helps.